United States

Main	Births etc

United States of America
Motto:  "In God We Trust" Other traditional mottos: "E pluribus unum"(Latin) "Out of many, one" "Annuit cœptis"(Latin) "He has favored our undertakings" "Novus ordo seclorum"(Latin) "New order of the ages"
Anthem:  "The Star-Spangled Banner"
Great Seal:
The United States, including its territories
Capital		Washington, D.C. 38°53′N 77°01′W
Largest city		New York City 40°43′N 74°00′W
Official languages		None at federal level
National language		English
Ethnic groups (2018)		By race: 76.5% White 13.4% Black 5.9% Asian 2.7% Other/multiracial 1.3% Native American 0.2% Pacific Islander Ethnicity: 18.3% Hispanic or Latino 81.7% non-Hispanic or Latino
Demonym		American
Government		Federal presidential constitutional republic
-	President	Donald Trump (R)
-	Vice President	Mike Pence (R)
-	House Speaker	Nancy Pelosi (D)
-	Chief Justice	John Roberts
Legislature		Congress
-	Upper house	Senate
-	Lower house	House of Representatives
Independence from Great Britain
-	Declaration	July 4, 1776
-	Articles of Confederation	March 1, 1781
-	Treaty of Paris	September 3, 1783
-	Current constitution	June 21, 1788
-	Bill of Rights	September 25, 1789
-	Last state admitted	August 21, 1959
-	Last amendment	May 5, 1992
-	Water (%)	6.97
-	Total land area	3,531,905 sq mi (9,147,590 km2)
Population
-	2019 estimate	328,239,523 (3rd)
-	2010 census	308,745,538 (3rd)
GDP (PPP)		2020 estimate
-	Total	$22.321 trillion (2nd)
-	Per capita	$67,426 (11th)
GDP (nominal)		2020 estimate
-	Total	$22.321 trillion (1st)
-	Per capita	$67,426 (7th)
Gini (2017)		39.0 medium · 56th
HDI (2018)		0.920 very high · 15th
Currency		[[{{#property:p38}}]] ($) (USD)
Time zone		(UTC−4 to −12, +10, +11)
-	Summer (DST)	(UTC−4 to −10)
Date format		mm/dd/yyyy yyyy-mm-dd
Drives on the		right
Calling code		+1
ISO 3166 code		US
Internet TLD		; Generic top-level domain: .com, .org, .net, .edu, .gov, .mil ccTLD (generally not used in the U.S.) .us, .pr, .as, .gu, .mp, .vi and, formerly, .um (removed by ICANN in 2008, but still recognized by the U.S. government as a ccTLD)

The United States of America (USA), commonly known as the United States (U.S. or US) or America, is a country mostly located in central North America, between Canada and Mexico. It consists of 50 states, a federal district, five major self-governing territories, and various possessions. At 3.8 million square miles (9.8 million km²), it is the world's third- or fourth-largest country by total area. With a 2019 estimated population of over 328 million, the U.S. is the third most populous country in the world. Americans are a racially and ethnically diverse population that has been shaped through centuries of immigration. The capital is Washington, D.C., and the most populous city is New York City.

Paleo-Indians migrated from Siberia to the North American mainland at least 12,000 years ago, and European colonization began in the 16th century. The United States emerged from the thirteen British colonies established along the East Coast. Numerous disputes between Great Britain and the colonies led to the American Revolutionary War lasting between 1775 and 1783, leading to independence. Beginning in the late 18th century, the United States vigorously expanded across North America, gradually acquiring new territories, killing and displacing Native Americans, and admitting new states. By 1848, the United States spanned the continent. Slavery was legal in much of the United States until the second half of the 19th century, when the American Civil War led to its abolition.

The Spanish–American War and World War I entrenched the U.S. as a world power, a status confirmed by the outcome of World War II. It was the first country to develop nuclear weapons and is the only country to have used them in warfare. During the Cold War, the United States and the Soviet Union competed in the Space Race, culminating with the 1969 Apollo 11 mission, the spaceflight that first landed humans on the Moon. The end of the Cold War and collapse of the Soviet Union in 1991 left the United States as the world's sole superpower.

The United States is a federal republic and a representative democracy. It is a founding member of the United Nations, World Bank, International Monetary Fund, Organization of American States (OAS), NATO, and other international organizations. It is a permanent member of the United Nations Security Council.

A highly developed country, the United States is the world's largest economy and accounts for approximately a quarter of global gross domestic product (GDP). The United States is the world's largest importer and the second-largest exporter of goods, by value. Although its population is only 4.3% of the world total, it holds 29.4% of the total wealth in the world, the largest share held by any country. Despite income and wealth disparities, the United States continues to rank very high in measures of socioeconomic performance, including average wage, median income, median wealth, human development, per capita GDP, and worker productivity. It is the foremost military power in the world, making up more than a third of global military spending, and is a leading political, cultural, and scientific force internationally.

Etymology

See also: Naming of the Americas, Names for United States citizens, and American (word)

The first known use of the name "America" dates back to 1507, when it appeared on a world map created by the German cartographer Martin Waldseemüller. On this map, the name applied to South America in honor of the Italian explorer Amerigo Vespucci. After returning from his expeditions, Vespucci first postulated that the West Indies did not represent Asia's eastern limit, as initially thought by Christopher Columbus, but instead were part of an entirely separate landmass thus far unknown to the Europeans. In 1538, the Flemish cartographer Gerardus Mercator used the name "America" on his own world map, applying it to the entire Western Hemisphere.

The first documentary evidence of the phrase "United States of America" dates from a January 2, 1776 letter written by Stephen Moylan, Esq., to Lt. Col. Joseph Reed, George Washington's aide-de-camp and Muster-Master General of the Continental Army. Moylan expressed his wish to go "with full and ample powers from the United States of America to Spain" to seek assistance in the revolutionary war effort. The first known publication of the phrase "United States of America" was in an anonymous essay in The Virginia Gazette newspaper in Williamsburg, Virginia, on April 6, 1776.

The second draft of the Articles of Confederation, prepared by John Dickinson and completed no later than June 17, 1776, declared "The name of this Confederation shall be the 'United States of America'". The final version of the Articles sent to the states for ratification in late 1777 contains the sentence "The Stile of this Confederacy shall be 'The United States of America'". In June 1776, Thomas Jefferson wrote the phrase "UNITED STATES OF AMERICA" in all capitalized letters in the headline of his "original Rough draught" of the Declaration of Independence. This draft of the document did not surface until June 21, 1776, and it is unclear whether it was written before or after Dickinson used the term in his June 17 draft of the Articles of Confederation.

The short form "United States" is also standard. Other common forms are the "U.S.," the "USA," and "America." Colloquial names are the "U.S. of A." and, internationally, the "States." "Columbia," a name popular in poetry and songs of the late 18th century, derives its origin from Christopher Columbus; it appears in the name "District of Columbia." Many landmarks and institutions in the Western Hemisphere bear his name, including the country of Colombia.

The phrase "United States" was originally plural, a description of a collection of independent states—e.g., "the United States are"—including in the Thirteenth Amendment to the United States Constitution, ratified in 1865. The singular form—e.g., "the United States is"—became popular after the end of the Civil War. The singular form is now standard; the plural form is retained in the idiom "these United States." The difference is more significant than usage; it is a difference between a collection of states and a unit.

A citizen of the United States is an "American." "United States," "American" and "U.S." refer to the country adjectivally ("American values," "U.S. forces"). In English, the word "American" rarely refers to topics or subjects not directly connected with the United States.

History

Main articles: History of the United States, Timeline of United States history, American business history, Economic history of the United States, and Labor history of the United States

Indigenous peoples and pre-Columbian history

Further information: Native Americans in the United States and Pre-Columbian era

The Cliff Palace, built by ancient Native American Puebloans around 1190 AD

It has been generally accepted that the first inhabitants of North America migrated from Siberia by way of the Bering land bridge and arrived at least 12,000 years ago; however, increasing evidence suggests an even earlier arrival. After crossing the land bridge, the Paleo-Indians moved southward along the Pacific coast and through an interior ice-free corridor. The Clovis culture, which appeared around 11,000 BC, was initially believed to represent the first wave of human settlement of the Americas. Increasing evidence has also been found for "pre-Clovis" cultures, including the recent discovery of tools dating back some 15,550 years. It is likely these represent the first of three major waves of migration into North America.

Over time, indigenous cultures in North America grew increasingly complex, and some, such as the pre-Columbian Mississippian culture in the southeast, developed advanced agriculture, grand architecture, and state-level societies. The Mississippian culture flourished in the south from 800 to 1600 AD, extending from the Mexican border down through Florida. Its city state Cahokia is the largest, most complex pre-Columbian archaeological site in the modern-day United States. In the Four Corners region, Ancestral Puebloan culture developed from centuries of agricultural experimentation.

Three UNESCO World Heritage Sites in the United States are credited to the Pueblos: Mesa Verde National Park, Chaco Culture National Historical Park, and Taos Pueblo. The earthworks constructed by Native Americans of the Poverty Point culture have also been designated a UNESCO World Heritage site. In the southern Great Lakes region, the Iroquois Confederacy was established at some point between the twelfth and fifteenth centuries. Most prominent along the Atlantic coast were the Algonquian tribes, who practiced hunting and trapping, along with limited cultivation.

Effects on and interaction with native populations

Further information: American Indian Wars, Population history of indigenous peoples of the Americas, and Native American disease and epidemics

Alaskan Alutiiq dancer in traditional festival garb

With the progress of European colonization in the territories of the contemporary United States, the Native Americans were often conquered and displaced. The native population of America declined after European arrival for various reasons, primarily diseases such as smallpox and measles.

Estimating the native population of North America at the time of European contact is difficult. Douglas H. Ubelaker of the Smithsonian Institution estimated that there was a population of 92,916 in the south Atlantic states and a population of 473,616 in the Gulf states, but most academics regard this figure as too low. Anthropologist Henry F. Dobyns believed the populations were much higher, suggesting 1,100,000 along the shores of the gulf of Mexico, 2,211,000 people living between Florida and Massachusetts, 5,250,000 in the Mississippi Valley and tributaries and 697,000 people in the Florida peninsula.

In the early days of colonization, many European settlers were subject to food shortages, disease, and attacks from Native Americans. Native Americans were also often at war with neighboring tribes and allied with Europeans in their colonial wars. In many cases, however, natives and settlers came to depend on each other. Settlers traded for food and animal pelts; natives for guns, ammunition and other European goods. Natives taught many settlers to cultivate corn, beans, and squash. European missionaries and others felt it was important to "civilize" the Native Americans and urged them to adopt European agricultural techniques and lifestyles.

European settlements

Further information: Colonial history of the United States, European colonization of the Americas, and Thirteen Colonies

Mayflower in Plymouth Harbor by William Halsall

With the advancement of European colonization in North America, the Native Americans were often conquered and displaced. The first Europeans to arrive in the contiguous United States were Spanish conquistadors such as Juan Ponce de León, who made his first visit to Florida in 1513. Even earlier, Christopher Columbus landed in Puerto Rico on his 1493 voyage. The Spanish set up the first settlements in Florida and New Mexico such as Saint Augustine and Santa Fe. The French established their own as well along the Mississippi River. Successful English settlement on the eastern coast of North America began with the Virginia Colony in 1607 at Jamestown and with the Pilgrims' Plymouth Colony in 1620. Many settlers were dissenting Christian groups who came seeking religious freedom. The continent's first elected legislative assembly, Virginia's House of Burgesses, was created in 1619. The Mayflower Compact, signed by the Pilgrims before disembarking, and the Fundamental Orders of Connecticut, established precedents for the pattern of representative self-government and constitutionalism that would develop throughout the American colonies.

Most settlers in every colony were small farmers, though other industries were formed. Cash crops included tobacco, rice, and wheat. Extraction industries grew up in furs, fishing and lumber. Manufacturers produced rum and ships, and by the late colonial period, Americans were producing one-seventh of the world's iron supply. Cities eventually dotted the coast to support local economies and serve as trade hubs. English colonists were supplemented by waves of Scotch-Irish immigrants and other groups. As coastal land grew more expensive, freed indentured servants claimed lands further west.

File:North America 1748.PNG

European territorial claims during the mid-18th century

A large-scale slave trade with English privateers began. Because of less disease and better food and treatment, the life expectancy of slaves was much higher in North America than further south, leading to a rapid increase in the numbers of slaves. Colonial society was largely divided over the religious and moral implications of slavery, and colonies passed acts for and against the practice. But by the turn of the 18th century, African slaves were replacing indentured servants for cash crop labor, especially in the South.

With the establishment of the Province of Georgia in 1732, the 13 colonies that would become the United States of America were administered by the British as overseas dependencies. All nonetheless had local governments with elections open to most free men. With extremely high birth rates, low death rates, and steady settlement, the colonial population grew rapidly. Relatively small Native American populations were eclipsed. The Christian revivalist movement of the 1730s and 1740s known as the Great Awakening fueled interest both in religion and in religious liberty.

During the Seven Years' War (known in the United States as the French and Indian War), British forces seized Canada from the French, but the francophone population remained politically isolated from the southern colonies. Excluding the Native Americans, who were being conquered and displaced, the 13 British colonies had a population of over 2.1 million in 1770, about a third that of Britain. Despite continuing, new arrivals, the rate of natural increase was such that by the 1770s only a small minority of Americans had been born overseas. The colonies' distance from Britain had allowed the development of self-government, but their unprecedented success motivated monarchs to periodically seek to reassert royal authority.

In 1774, the Spanish Navy ship Santiago, under Juan Pérez, entered and anchored in an inlet of Nootka Sound, Vancouver Island, in present-day British Columbia. Although the Spanish did not land, natives paddled to the ship to trade furs for abalone shells from California. At the time, the Spanish were able to monopolize the trade between Asia and North America, granting limited licenses to the Portuguese. When the Russians began establishing a growing fur trading system in Alaska, the Spanish began to challenge the Russians, with Pérez's voyage being the first of many to the Pacific Northwest.

During his third and final voyage, Captain James Cook became the first European to begin formal contact with Hawaii. Captain Cook's last voyage included sailing along the coast of North America and Alaska searching for a Northwest Passage for approximately nine months.

Independence and expansion (1776–1865)

Further information: American Revolutionary War, United States Declaration of Independence, American Revolution, and Territorial evolution of the United States

Declaration of Independence, by John Trumbull (1819), depicts the Committee of Five presenting their draft of the Declaration to the Continental Congress

The American Revolutionary War was the first successful colonial war of independence against a European power. Americans had developed an ideology of "republicanism" asserting that government rested on the will of the people as expressed in their local legislatures. They demanded their rights as Englishmen and "no taxation without representation". The British insisted on administering the empire through Parliament, and the conflict escalated into war.

The Second Continental Congress unanimously adopted the Declaration of Independence, which asserted that Great Britain was not protecting Americans' unalienable rights. July 4 is celebrated annually as Independence Day. In 1777, the Articles of Confederation established a decentralized government that operated until 1789.

Map of territorial acquisitions of the United States between 1783 and 1917

Following the decisive Franco-American victory at Yorktown in 1781, Britain signed the peace treaty of 1783, and American sovereignty was internationally recognized and the country was granted all lands east of the Mississippi River. Nationalists led the Philadelphia Convention of 1787 in writing the United States Constitution, ratified in state conventions in 1788. The federal government was reorganized into three branches, on the principle of creating salutary checks and balances, in 1789. George Washington, who had led the Continental Army to victory, was the first president elected under the new constitution. The Bill of Rights, forbidding federal restriction of personal freedoms and guaranteeing a range of legal protections, was adopted in 1791.

Although the federal government criminalized the international slave trade in 1808, after 1820, cultivation of the highly profitable cotton crop exploded in the Deep South, and along with it, the slave population. The Second Great Awakening, especially 1800–1840, converted millions to evangelical Protestantism. In the North, it energized multiple social reform movements, including abolitionism; in the South, Methodists and Baptists proselytized among slave populations.

Americans' eagerness to expand westward prompted a long series of American Indian Wars. The Louisiana Purchase of French-claimed territory in 1803 almost doubled the nation's area. The War of 1812, declared against Britain over various grievances and fought to a draw, strengthened U.S. nationalism. A series of military incursions into Florida led Spain to cede it and other Gulf Coast territory in 1819. The expansion was aided by steam power, when steamboats began traveling along America's large water systems, many of which were connected by new canals, such as the Erie and the I&M; then, even faster railroads began their stretch across the nation's land.

San Francisco harbor during the California Gold Rush

From 1820 to 1850, Jacksonian democracy began a set of reforms which included wider white male suffrage; it led to the rise of the Second Party System of Democrats and Whigs as the dominant parties from 1828 to 1854. The Trail of Tears in the 1830s exemplified the Indian removal policy that forcibly resettled Indians into the west on Indian reservations. The U.S. annexed the Republic of Texas in 1845 during a period of expansionist Manifest destiny. The 1846 Oregon Treaty with Britain led to U.S. control of the present-day American Northwest. Victory in the Mexican–American War resulted in the 1848 Mexican Cession of California and much of the present-day American Southwest. The California Gold Rush of 1848–49 spurred migration to the Pacific coast, which led to the California Genocide and the creation of additional western states. After the Civil War, new transcontinental railways made relocation easier for settlers, expanded internal trade and increased conflicts with Native Americans. In 1869, a new Peace Policy nominally promised to protect Native Americans from abuses, avoid further war, and secure their eventual U.S. citizenship. Nonetheless, large-scale conflicts continued throughout the West into the 1900s.

Civil War and Reconstruction era

Further information: American Civil War and Reconstruction era

President Abraham Lincoln in Gettysburg, Pennsylvania, November 19, 1863

Irreconcilable sectional conflict regarding the slavery of Africans and African Americans ultimately led to the American Civil War. Initially, states entering the Union had alternated between slave and free states, keeping a sectional balance in the Senate, while free states outstripped slave states in population and in the House of Representatives. But with additional western territory and more free-soil states, tensions between slave and free states mounted with arguments over federalism and disposition of the territories, as well as whether to expand or restrict slavery.

With the 1860 election of Republican Abraham Lincoln, conventions in thirteen slave states ultimately declared secession and formed the Confederate States of America (the "South" or the "Confederacy"), while the federal government (the "Union") maintained that secession was illegal. In order to bring about this secession, military action was initiated by the secessionists, and the Union responded in kind. The ensuing war would become the deadliest military conflict in American history, resulting in the deaths of approximately 618,000 soldiers as well as many civilians. The Union initially simply fought to keep the country united. Nevertheless, as casualties mounted after 1863 and Lincoln delivered his Emancipation Proclamation, the main purpose of the war from the Union's viewpoint became the abolition of slavery. Indeed, when the Union ultimately won the war in April 1865, each of the states in the defeated South was required to ratify the Thirteenth Amendment, which prohibited slavery.

The government enacted three constitutional amendments in the years after the war: the aforementioned Thirteenth as well as the Fourteenth Amendment providing citizenship to the nearly four million African Americans who had been slaves, and the Fifteenth Amendment ensuring in theory that African Americans had the right to vote. The war and its resolution led to a substantial increase in federal power aimed at reintegrating and rebuilding the South while guaranteeing the rights of the newly freed slaves.

Reconstruction began in earnest following the war. While President Lincoln attempted to foster friendship and forgiveness between the Union and the former Confederacy, his assassination on April 14, 1865, drove a wedge between North and South again. Republicans in the federal government made it their goal to oversee the rebuilding of the South and to ensure the rights of African Americans. They persisted until the Compromise of 1877 when the Republicans agreed to cease protecting the rights of African Americans in the South in order for Democrats to concede the presidential election of 1876.

Southern white Democrats, calling themselves "Redeemers," took control of the South after the end of Reconstruction. From 1890 to 1910 the Redeemers established so-called Jim Crow laws, disenfranchising most blacks and some poor whites throughout the region. Blacks faced racial segregation, especially in the South. They also occasionally experienced vigilante violence, including lynching.

Further immigration, expansion, and industrialization

Main articles: Economic history of the United States and Technological and industrial history of the United States

Ellis Island, in New York Harbor, was a major entry point for European immigration into the U.S.

In the North, urbanization and an unprecedented influx of immigrants from Southern and Eastern Europe supplied a surplus of labor for the country's industrialization and transformed its culture. National infrastructure including telegraph and transcontinental railroads spurred economic growth and greater settlement and development of the American Old West. The later invention of electric light and the telephone would also affect communication and urban life.

The United States fought Indian Wars west of the Mississippi River from 1810 to at least 1890. Most of these conflicts ended with the cession of Native American territory and their confinement to Indian reservations. This further expanded acreage under mechanical cultivation, increasing surpluses for international markets. Mainland expansion also included the purchase of Alaska from Russia in 1867. In 1893, pro-American elements in Hawaii overthrew the monarchy and formed the Republic of Hawaii, which the U.S. annexed in 1898. Puerto Rico, Guam, and the Philippines were ceded by Spain in the same year, following the Spanish–American War. American Samoa was acquired by the United States in 1900 after the end of the Second Samoan Civil War. The U.S. Virgin Islands were purchased from Denmark in 1917.

Rapid economic development during the late 19th and early 20th centuries fostered the rise of many prominent industrialists. Tycoons like Cornelius Vanderbilt, John D. Rockefeller, and Andrew Carnegie led the nation's progress in railroad, petroleum, and steel industries. Banking became a major part of the economy, with J. P. Morgan playing a notable role. The American economy boomed, becoming the world's largest, and the United States achieved great power status. These dramatic changes were accompanied by social unrest and the rise of populist, socialist, and anarchist movements. This period eventually ended with the advent of the Progressive Era, which saw significant reforms including women's suffrage, alcohol prohibition, regulation of consumer goods, greater antitrust measures to ensure competition and attention to worker conditions.

World War I, Great Depression, and World War II

Further information: World War I, Great Depression, and World War II

The Empire State Building was the tallest building in the world when completed in 1931, during the Great Depression.

The United States remained neutral from the outbreak of World War I in 1914 until 1917, when it joined the war as an "associated power," alongside the formal Allies of World War I, helping to turn the tide against the Central Powers. In 1919, President Woodrow Wilson took a leading diplomatic role at the Paris Peace Conference and advocated strongly for the U.S. to join the League of Nations. However, the Senate refused to approve this and did not ratify the Treaty of Versailles that established the League of Nations.

In 1920, the women's rights movement won passage of a constitutional amendment granting women's suffrage. The 1920s and 1930s saw the rise of radio for mass communication and the invention of early television. The prosperity of the Roaring Twenties ended with the Wall Street Crash of 1929 and the onset of the Great Depression. After his election as president in 1932, Franklin D. Roosevelt responded with the New Deal. The Great Migration of millions of African Americans out of the American South began before World War I and extended through the 1960s; whereas the Dust Bowl of the mid-1930s impoverished many farming communities and spurred a new wave of western migration.

U.S. troops landing on Omaha Beach during the invasion of Normandy, June 6, 1944

At first effectively neutral during World War II, the United States began supplying materiel to the Allies in March 1941 through the Lend-Lease program. On December 7, 1941, the Empire of Japan launched a surprise attack on Pearl Harbor, prompting the United States to join the Allies against the Axis powers. Although Japan attacked the United States first, the U.S. nonetheless pursued a "Europe first" defense policy. The United States thus left its vast Asian colony, the Philippines, isolated and fighting a losing struggle against Japanese invasion and occupation, as military resources were devoted to the European theater. During the war, the United States was referred to as one of the "Four Policemen" of Allies power who met to plan the postwar world, along with Britain, the Soviet Union and China. Although the nation lost around 400,000 military personnel, it emerged relatively undamaged from the war with even greater economic and military influence.

Trinity test of the Manhattan Project's nuclear weapon

The United States played a leading role in the Bretton Woods and Yalta conferences with the United Kingdom, the Soviet Union, and other Allies, which signed agreements on new international financial institutions and Europe's postwar reorganization. As an Allied victory was won in Europe, a 1945 international conference held in San Francisco produced the United Nations Charter, which became active after the war. The United States and Japan then fought each other in the largest naval battle in history, the Battle of Leyte Gulf. The United States eventually developed the first nuclear weapons and used them on Japan in the cities of Hiroshima and Nagasaki; the Japanese surrendered on September 2, ending World War II.

Cold War and civil rights era

Main articles: History of the United States (1945–1964), History of the United States (1964–1980), and History of the United States (1980–1991)

Further information: Cold War, Civil Rights Movement, War on Poverty, Space Race, and Reaganomics

Martin Luther King, Jr. gives his famous "I Have a Dream" speech at the Lincoln Memorial during the March on Washington, 1963

After World War II, the United States and the Soviet Union competed for power, influence, and prestige during what became known as the Cold War, driven by an ideological divide between capitalism and communism. They dominated the military affairs of Europe, with the U.S. and its NATO allies on one side and the USSR and its Warsaw Pact allies on the other. The U.S. developed a policy of containment towards the expansion of communist influence. While the U.S. and Soviet Union engaged in proxy wars and developed powerful nuclear arsenals, the two countries avoided direct military conflict.

The United States often opposed Third World movements that it viewed as Soviet-sponsored, and occasionally pursued direct action for regime change against left-wing governments, even supporting right-wing authoritarian governments at times. American troops fought communist Chinese and North Korean forces in the Korean War of 1950–53. The Soviet Union's 1957 launch of the first artificial satellite and its 1961 launch of the first manned spaceflight initiated a "Space Race" in which the United States became the first nation to land a man on the moon in 1969. A proxy war in Southeast Asia eventually evolved into full American participation, as the Vietnam War.

At home, the U.S. experienced sustained economic expansion and a rapid growth of its population and middle class. Construction of an Interstate Highway System transformed the nation's infrastructure over the following decades. Millions moved from farms and inner cities to large suburban housing developments. In 1959 Hawaii became the 50th and last U.S. state added to the country. The growing Civil Rights Movement used nonviolence to confront segregation and discrimination, with Martin Luther King Jr. becoming a prominent leader and figurehead. A combination of court decisions and legislation, culminating in the Civil Rights Act of 1968, sought to end racial discrimination. Meanwhile, a counterculture movement grew which was fueled by opposition to the Vietnam war, black nationalism, and the sexual revolution.

U.S. president Ronald Reagan (left) and Soviet general secretary Mikhail Gorbachev in Geneva, 1985

The launch of a "War on Poverty" expanded entitlements and welfare spending, including the creation of Medicare and Medicaid, two programs that provide health coverage to the elderly and poor, respectively, and the means-tested Food Stamp Program and Aid to Families with Dependent Children.

The 1970s and early 1980s saw the onset of stagflation. After his election in 1980, President Ronald Reagan responded to economic stagnation with free-market oriented reforms. Following the collapse of détente, he abandoned "containment" and initiated the more aggressive "rollback" strategy towards the USSR. After a surge in female labor participation over the previous decade, by 1985 the majority of women aged 16 and over were employed.

The late 1980s brought a "thaw" in relations with the USSR, and its collapse in 1991 finally ended the Cold War. This brought about unipolarity with the U.S. unchallenged as the world's dominant superpower. The concept of Pax Americana, which had appeared in the post-World War II period, gained wide popularity as a term for the post-Cold War new world order.

Geography, climate, and environment

Main articles: Geography of the United States, Climate of the United States, and Environment of the United States

A satellite composite image of the conterminous United States.

The 48 contiguous states and the District of Columbia occupy a combined area of 3,119,884.69 square miles (8,080,464.3 km²). Of this area, 2,959,064.44 square miles (7,663,941.7 km²) is contiguous land, composing 83.65% of total U.S. land area. Hawaii, occupying an archipelago in the central Pacific, southwest of North America, is 10,931 square miles (28,311 km²) in area. The populated territories of Puerto Rico, American Samoa, Guam, Northern Mariana Islands, and U.S. Virgin Islands together cover 9,185 square miles (23,789 km²). Measured by only land area, the United States is third in size behind Russia and China, just ahead of Canada.

The United States is the world's third- or fourth-largest nation by total area (land and water), ranking behind Russia and Canada and nearly equal to China. The ranking varies depending on how two territories disputed by China and India are counted, and how the total size of the United States is measured.

The coastal plain of the Atlantic seaboard gives way further inland to deciduous forests and the rolling hills of the Piedmont. The Appalachian Mountains divide the eastern seaboard from the Great Lakes and the grasslands of the Midwest. The Mississippi–Missouri River, the world's fourth longest river system, runs mainly north–south through the heart of the country. The flat, fertile prairie of the Great Plains stretches to the west, interrupted by a highland region in the southeast.

Köppen climate classifications of U.S. states and territories

The Rocky Mountains, west of the Great Plains, extend north to south across the country, peaking around 14,000 feet (4,300 m) in Colorado. Farther west are the rocky Great Basin and deserts such as the Chihuahua and Mojave. The Sierra Nevada and Cascade mountain ranges run close to the Pacific coast, both ranges reaching altitudes higher than 14,000 feet (4,300 m). The lowest and highest points in the contiguous United States are in the state of California, and only about 84 miles (135 km) apart. At an elevation of 20,310 feet (6,190.5 m), Alaska's Denali is the highest peak in the country and in North America. Active volcanoes are common throughout Alaska's Alexander and Aleutian Islands, and Hawaii consists of volcanic islands. The supervolcano underlying Yellowstone National Park in the Rockies is the continent's largest volcanic feature.

The United States, with its large size and geographic variety, includes most climate types. To the east of the 100th meridian, the climate ranges from humid continental in the north to humid subtropical in the south. The Great Plains west of the 100th meridian are semi-arid. Much of the Western mountains have an alpine climate. The climate is arid in the Great Basin, desert in the Southwest, Mediterranean in coastal California, and oceanic in coastal Oregon and Washington and southern Alaska. Most of Alaska is subarctic or polar. Hawaii and the southern tip of Florida are tropical, as well as its territories in the Caribbean and the Pacific. States bordering the Gulf of Mexico are prone to hurricanes, and most of the world's tornadoes occur in the country, mainly in Tornado Alley areas in the Midwest and South. Overall, the United States has the world's most violent weather, receiving more high-impact extreme weather incidents than any other country in the world.

Wildlife and conservation

Main articles: Fauna of the United States and Flora of the United States

See also: Category:Biota of the United States

The bald eagle has been the national bird of the United States since 1782.

The U.S. ecology is megadiverse: about 17,000 species of vascular plants occur in the contiguous United States and Alaska, and more than 1,800 species of flowering plants are found in Hawaii, few of which occur on the mainland. The United States is home to 428 mammal species, 784 bird species, 311 reptile species, and 295 amphibian species, as well as about 91,000 insect species.

There are 62 national parks and hundreds of other federally managed parks, forests, and wilderness areas. Altogether, the government owns about 28% of the country's land area, mostly in the western states. Most of this land is protected, though some is leased for oil and gas drilling, mining, logging, or cattle ranching, and about .86% is used for military purposes.

Environmental issues include debates on oil and nuclear energy, dealing with air and water pollution, the economic costs of protecting wildlife, logging and deforestation, and international responses to global warming. The most prominent environmental agency is the Environmental Protection Agency (EPA), created by presidential order in 1970. The idea of wilderness has shaped the management of public lands since 1964, with the Wilderness Act. The Endangered Species Act of 1973 is intended to protect threatened and endangered species and their habitats, which are monitored by the United States Fish and Wildlife Service.

Demographics

Main articles: Americans, Demographics of the United States, and Race and ethnicity in the United States

Population

See also: List of U.S. states by population and List of United States cities by population

Historical populations
Census	Pop.		%±
1790	3,929,214		—
1800	5,308,483		35.1%
1810	7,239,881		36.4%
1820	9,638,453		33.1%
1830	12,866,020		33.5%
1840	17,069,453		32.7%
1850	23,191,876		35.9%
1860	31,443,321		35.6%
1870	38,558,371		22.6%
1880	50,189,209		30.2%
1890	62,979,766		25.5%
1900	76,212,168		21.0%
1910	92,228,496		21.0%
1920	106,021,537		15.0%
1930	123,202,624		16.2%
1940	132,164,569		7.3%
1950	151,325,798		14.5%
1960	179,323,175		18.5%
1970	203,211,926		13.3%
1980	226,545,805		11.5%
1990	248,709,873		9.8%
2000	281,421,906		13.2%
2010	308,745,538		9.7%
Est. 2019	328,239,523		16.6%
1610–1780 population data. Note that the census numbers do not include Native Americans until 1860.

Population by state (2015):

  580k–2.8M

  2.8M–5.28M

  5.28M–8.26M

  8.26M–11.6M

  11.6M–19.6M

  19.6M–26.5M

  26.5M–38.4M

  38.4M+

The U.S. Census Bureau officially estimated the country's population to be 328,239,523 as of July 1, 2019. In addition, the Census Bureau provides a continuously updated U.S. Population Clock that approximates the latest population of the 50 states and District of Columbia based on the Bureau's most recent demographic trends. According to the clock, on May 23, 2020, the U.S. population exceeded 329 million residents, with a net gain of one person every 19 seconds, or about 4,547 people per day. The United States is the third most populous nation in the world, after China and India. In 2018 the median age of the United States population was 38.1 years.

In 2018, there were almost 90 million immigrants and U.S.-born children of immigrants (second-generation Americans) in the United States, accounting for 28% of the overall U.S. population. The United States has a very diverse population; 37 ancestry groups have more than one million members. German Americans are the largest ethnic group (more than 50 million)—followed by Irish Americans (circa 37 million), Mexican Americans (circa 31 million) and English Americans (circa 28 million).

White Americans (mostly European ancestry) are the largest racial group at 73.1% of the population; African Americans are the nation's largest racial minority and third-largest ancestry group. Asian Americans are the country's second-largest racial minority; the three largest Asian American ethnic groups are Chinese Americans, Filipino Americans, and Indian Americans. The largest American community with European ancestry is German Americans, which consists of more than 14% of the total population. In 2010, the U.S. population included an estimated 5.2 million people with some American Indian or Alaska Native ancestry (2.9 million exclusively of such ancestry) and 1.2 million with some native Hawaiian or Pacific island ancestry (0.5 million exclusively). The census counted more than 19 million people of "Some Other Race" who were "unable to identify with any" of its five official race categories in 2010, more than 18.5 million (97%) of whom are of Hispanic ethnicity.

Minorities, defined by the Census Bureau as all individuals aside from non-Hispanic, non-multiracial whites, constituted 37% of the population in 2012. More than 50% of infants less than a year old are members of minority groups. These groups are projected to collectively make up a majority of the population by 2044.

In 2017, out of the U.S. foreign-born population, some 45% (20.7 million) were naturalized citizens, 27% (12.3 million) were lawful permanent residents (including many eligible to become citizens), 6% (2.2 million) were temporary lawful residents, and 23% (10.5 million) were unauthorized immigrants. Among current living immigrants to the U.S., the top five countries of birth are Mexico, China, India, the Philippines and El Salvador. Until 2017 and 2018, the United States led the word in refugee resettlement for decades, admitted more refugees than the rest of the world combined. From fiscal year 1980 until 2017, 55% of refugees came from Asia, 27% from Europe, 13% from Africa, and 4% from Latin America.

A 2017 Gallup poll concluded that 4.5% of adult Americans identified as LGBT with 5.1% of women identifying as LGBT, compared with 3.9% of men. The highest percentage came from the District of Columbia (10%), while the lowest state was North Dakota at 1.7%.

A 2017 United Nations report projected that the U.S. would be one of nine countries in which world population growth through 2050 would be concentrated. A 2020 U.S. Census Bureau report projected the population of the country could be anywhere between 320 million and 447 million by 2060, depending on the rate of in-migration; in all projected scenarios, a lower fertility rate and increases in life expectancy would result in an aging population.

The population growth of Hispanic and Latino Americans is a major demographic trend. The 50.5 million Americans of Hispanic descent are identified as sharing a distinct "ethnicity" by the Census Bureau; 64% of Hispanic Americans are of Mexican descent. Between 2000 and 2010, the country's Hispanic population increased 43% while the non-Hispanic population rose just 4.9%.

The United States has an annual birth rate of 13 per 1,000, which is five births per 1,000 below the world average. Its population growth rate is positive at 0.7%, higher than that of many developed nations. In fiscal year 2017, more than a million immigrants (most of whom entered through family reunification) were granted legal residence. In absolute numbers, the number of foreign-born U.S. residents is at a record high (44.4 million in 2017); however as a proportion of the overall population, the current foreign-born share (13.6% of the total population) is lower than the share at the peak in 1890 (14.8% of the total population).

About 82% of Americans live in urban areas (including suburbs); about half of those reside in cities with populations over 50,000. In 2008, 273 incorporated municipalities had populations over 100,000, nine cities had more than one million residents, and four cities had over two million (namely New York, Los Angeles, Chicago, and Houston). Estimates for the year 2018 show that 53 metropolitan areas have populations greater than one million. Many metros in the South, Southwest and West grew significantly between 2010 and 2018. The Dallas and Houston metros increased by more than a million people, while the Washington, D.C., Miami, Atlanta, and Phoenix metros all grew by more than 500,000 people.

Language

Main article: Languages of the United States

See also: Language Spoken at Home in the United States of America, List of endangered languages in the United States, and Language education in the United States

English (specifically, American English) is the de facto national language of the United States. Although there is no official language at the federal level, some laws—such as U.S. naturalization requirements—standardize English. In 2010, about 230 million, or 80% of the population aged five years and older, spoke only English at home. 12% of the population speaks Spanish at home, making it the second most common language. Spanish is also the most widely taught second language.

Both Hawaiian and English are official languages in Hawaii. In addition to English, Alaska recognizes twenty official Native languages, and South Dakota recognizes Sioux. While neither has an official language, New Mexico has laws providing for the use of both English and Spanish, as Louisiana does for English and French. Other states, such as California, mandate the publication of Spanish versions of certain government documents including court forms.

Several insular territories grant official recognition to their native languages, along with English: Samoan is officially recognized by American Samoa and Chamorro is an official language of Guam. Both Carolinian and Chamorro have official recognition in the Northern Mariana Islands. Spanish is an official language of Puerto Rico and is more widely spoken than English there.

The most widely taught foreign languages in the United States, in terms of enrollment numbers from kindergarten through university undergraduate education, are Spanish (around 7.2 million students), French (1.5 million), and German (500,000). Other commonly taught languages include Latin, Japanese, ASL, Italian, and Chinese. 18% of all Americans claim to speak both English and another language.

Languages spoken at home by more than one million persons in the U.S. (2016)

Language	Percent of population	Number of speakers	Number who speak English very well	Number who speak English less than very well
English (only)	~80%	237,810,023	N/A	N/A
Spanish (including Spanish Creole but excluding residents of Puerto Rico)	13%	40,489,813	23,899,421	16,590,392
Chinese (all varieties, including Mandarin and Cantonese)	1.0%	3,372,930	1,518,619	1,854,311
Tagalog (including Filipino)	0.5%	1,701,960	1,159,211	542,749
Vietnamese	0.4%	1,509,993	634,273	875,720
Arabic (all varieties)	0.3%	1,231,098	770,882	460,216
French (including Patois and Cajun)	0.3%	1,216,668	965,584	251,087
Korean	0.2%	1,088,788	505,734	583,054

Religion

Main article: Religion in the United States

Religion in the United States (2017)

  Protestantism (48.5%)

  Catholicism (22.7%)

  Mormonism (1.8%)

  No religion (21.3%)

  Judaism (2.1%)

  Islam (0.8%)

  Other non-Abrahamic religion (e.g. Hinduism, Buddhism, and Sikhism) (2.9%)

The First Amendment of the U.S. Constitution guarantees the free exercise of religion and forbids Congress from passing laws respecting its establishment.

In a 2013 survey, 56% of Americans said religion played a "very important role in their lives," a far higher figure than that of any other Western nation. In a 2009 Gallup poll, 42% of Americans said they attended church weekly or almost weekly; the figures ranged from a low of 23% in Vermont to a high of 63% in Mississippi.

In a 2014 survey, 70.6% of adults in the United States identified themselves as Christians; Protestants accounted for 46.5%, while Roman Catholics, at 20.8%, formed the largest single denomination. In 2014, 5.9% of the U.S. adult population claimed a non-Christian religion. These include Judaism (1.9%), Islam (0.9%), Hinduism (0.7%), and Buddhism (0.7%). The survey also reported that 22.8% of Americans described themselves as agnostic, atheist or simply having no religion—up from 8.2% in 1990. There are also Unitarian Universalist, Scientologist, Baha'i, Sikh, Jain, Shinto, Zoroastrian, Confucian, Satanist, Taoist, Druid, Native American, Afro-American, traditional African, Wiccan, Gnostic, humanist and deist communities.

Protestantism is the largest Christian religious grouping in the United States, accounting for almost half of all Americans. Baptists collectively form the largest branch of Protestantism at 15.4%, and the Southern Baptist Convention is the largest individual Protestant denomination at 5.3% of the U.S. population. Apart from Baptists, other Protestant categories include nondenominational Protestants, Methodists, Pentecostals, unspecified Protestants, Lutherans, Presbyterians, Congregationalists, other Reformed, Episcopalians/Anglicans, Quakers, Adventists, Holiness, Christian fundamentalists, Anabaptists, Pietists, and multiple others.

As with other Western countries, the U.S. is becoming less religious. Irreligion is growing rapidly among Americans under 30. Polls show that overall American confidence in organized religion has been declining since the mid to late 1980s, and that younger Americans, in particular, are becoming increasingly irreligious. In a 2012 study, the Protestant share of the U.S. population had dropped to 48%, thus ending its status as religious category of the majority for the first time. Americans with no religion have 1.7 children compared to 2.2 among Christians. The unaffiliated are less likely to marry with 37% marrying compared to 52% of Christians.

The Bible Belt is an informal term for a region in the Southern United States in which socially conservative evangelical Protestantism is a significant part of the culture and Christian church attendance across the denominations is generally higher than the nation's average. By contrast, religion plays the least important role in New England and in the Western United States.

Family structure

Main article: Family structure in the United States

As of 2018, 52% of Americans age 15 and over were married, 6% were widowed, 10% were divorced, and 32% had never been married. Women now work mostly outside the home and receive the majority of bachelor's degrees.

The U.S. teenage pregnancy rate is 26.5 per 1,000 women. The rate has declined by 57% since 1991. Abortion is legal throughout the country. Abortion rates, currently 241 per 1,000 live births and 15 per 1,000 women aged 15–44, are falling but remain higher than most Western nations. In 2013, the average age at first birth was 26 and 41% of births were to unmarried women.

The total fertility rate in 2016 was 1820.5 births per 1000 women. Adoption in the United States is common and relatively easy from a legal point of view (compared to other Western countries). As of 2001, with more than 127,000 adoptions, the U.S. accounted for nearly half of the total number of adoptions worldwide.Template:Update inline Same-sex marriage is legal nationwide, and it is legal for same-sex couples to adopt. Polygamy is illegal throughout the U.S.

The U.S. has the world's highest rate of children living in single-parent households.

Health

See also: Health care in the United States, Health care reform in the United States, and Health insurance in the United States

The Texas Medical Center in downtown Houston is the largest medical complex in the world.

The United States had a life expectancy of 78.6 years at birth in 2017, which was the third year of declines in life expectancy following decades of continuous increase. The recent decline, primarily among the age group 25 to 64, is largely due to sharp increases in the drug overdose and suicide rates; the country has one of the highest suicide rates among wealthy countries. Life expectancy was highest among Asians and Hispanics and lowest among blacks. According to CDC and Census Bureau data, deaths from suicide, alcohol and drug overdoses hit record highs in 2017.

Increasing obesity in the United States and health improvements elsewhere contributed to lowering the country's rank in life expectancy from 11th in the world in 1987, to 42nd in 2007, and as of 2017 the country had the lowest life expectancy among Japan, Canada, Australia, the UK, and seven countries of western Europe. Obesity rates have more than doubled in the last 30 years and are the highest in the industrialized world. Approximately one-third of the adult population is obese and an additional third is overweight. Obesity-related type 2 diabetes is considered epidemic by health care professionals.

In 2010, coronary artery disease, lung cancer, stroke, chronic obstructive pulmonary diseases, and traffic accidents caused the most years of life lost in the U.S. Low back pain, depression, musculoskeletal disorders, neck pain, and anxiety caused the most years lost to disability. The most harmful risk factors were poor diet, tobacco smoking, obesity, high blood pressure, high blood sugar, physical inactivity, and alcohol use. Alzheimer's disease, drug abuse, kidney disease, cancer, and falls caused the most additional years of life lost over their age-adjusted 1990 per-capita rates. U.S. teenage pregnancy and abortion rates are substantially higher than in other Western nations, especially among blacks and Hispanics.

Health-care coverage in the United States is a combination of public and private efforts and is not universal. In 2017, 12.2% of the population did not carry health insurance. The subject of uninsured and underinsured Americans is a major political issue. Federal legislation, passed in early 2010, roughly halved the uninsured share of the population, though the bill and its ultimate effect are issues of controversy. The U.S. health-care system far outspends any other nation, measured both in per capita spending and as percentage of GDP. At the same time, the U.S. is a global leader in medical innovation.

Education

Main articles: Education in the United States and Higher education in the United States

The University of Virginia, founded by Thomas Jefferson in 1819, is one of the many public universities in the United States. Universal government-funded education exists in the United States, while there are also many privately funded institutions.

American public education is operated by state and local governments, regulated by the United States Department of Education through restrictions on federal grants. In most states, children are required to attend school from the age of six or seven (generally, kindergarten or first grade) until they turn 18 (generally bringing them through twelfth grade, the end of high school); some states allow students to leave school at 16 or 17.

About 12% of children are enrolled in parochial or nonsectarian private schools. Just over 2% of children are homeschooled. The U.S. spends more on education per student than any nation in the world, spending more than $11,000 per elementary student in 2010 and more than $12,000 per high school student.Template:Needs update Some 80% of U.S. college students attend public universities.

Of Americans 25 and older, 84.6% graduated from high school, 52.6% attended some college, 27.2% earned a bachelor's degree, and 9.6% earned graduate degrees. The basic literacy rate is approximately 99%. The United Nations assigns the United States an Education Index of 0.97, tying it for 12th in the world.

The United States has many private and public institutions of higher education. The majority of the world's top universities, as listed by various ranking organizations, are in the U.S. There are also local community colleges with generally more open admission policies, shorter academic programs, and lower tuition.

In 2018, U21, a network of research-intensive universities, ranked the United States first in the world for breadth and quality of higher education, and 15th when GDP was a factor. As for public expenditures on higher education, the U.S. trails some other OECD nations but spends more per student than the OECD average, and more than all nations in combined public and private spending. As of 2018, student loan debt exceeded 1.5 trillion dollars.

Law enforcement and crime

Main articles: Law enforcement in the United States and Crime in the United States

See also: Law of the United States, Human rights in the United States#Justice system, Incarceration in the United States, and Police brutality in the United States

The New York Police Department (NYPD) is the largest in the country.

Law enforcement in the United States is primarily the responsibility of local police departments and sheriff's offices, with state police providing broader services. Federal agencies such as the Federal Bureau of Investigation (FBI) and the U.S. Marshals Service have specialized duties, including protecting civil rights, national security and enforcing U.S. federal courts' rulings and federal laws. State courts conduct most criminal trials while federal courts handle certain designated crimes as well as certain appeals from the state criminal courts.

A cross-sectional analysis of the World Health Organization Mortality Database from 2010 showed that United States "homicide rates were 7.0 times higher than in other high-income countries, driven by a gun homicide rate that was 25.2 times higher." In 2016, the US murder rate was 5.4 per 100,000. Gun ownership rights, guaranteed by the Second Amendment, continue to be the subject of contention.

Total incarceration in the United States by year

The United States has the highest documented incarceration rate and largest prison population in the world. As of 2020, the Prison Policy Initiative reported that there were some 2.3 million people incarcerated. The imprisonment rate for all prisoners sentenced to more than a year in state or federal facilities is 478 per 100,000 in 2013. According to the Federal Bureau of Prisons, the majority of inmates held in federal prisons are convicted of drug offenses. About 9% of prisoners are held in privatized prisons. The practice of privately operated prisons began in the 1980s and has been a subject of contention.

Capital punishment is sanctioned in the United States for certain federal and military crimes, and at the state level in 30 states. No executions took place from 1967 to 1977, owing in part to a U.S. Supreme Court ruling striking down arbitrary imposition of the death penalty. Since the decision there have been more than 1,300 executions, a majority of these taking place in three states: Texas, Virginia, and Oklahoma. Meanwhile, several states have either abolished or struck down death penalty laws. In 2019, the country had the sixth-highest number of executions in the world, following China, Iran, Saudi Arabia, Iraq, and Egypt.

Economy

Main article: Economy of the United States

See also: Economic history of the United States

Economic indicators
Nominal GDP	$20.66 trillion (Q3 2018)
Real GDP growth	3.5% (Q3 2018)
	2.1% (2017)
CPI inflation	2.2% (November 2018)
Employment-to-population ratio	60.6% (November 2018)
Unemployment	3.7% (November 2018)
Labor force participation rate	62.9% (November 2018)
Total public debt	$21.85 trillion (November 2018)
Household net worth	$109.0 trillion (Q3 2018)

According to the International Monetary Fund, the U.S. GDP of $16.8 trillion constitutes 24% of the gross world product at market exchange rates and over 19% of the gross world product at purchasing power parity (PPP). The United States is the largest importer of goods and second-largest exporter, though exports per capita are relatively low. In 2010, the total U.S. trade deficit was $635 billion. Canada, China, Mexico, Japan, and Germany are its top trading partners.

From 1983 to 2008, U.S. real compounded annual GDP growth was 3.3%, compared to a 2.3% weighted average for the rest of the G7. The country ranks ninth in the world in nominal GDP per capita and sixth in GDP per capita at PPP. The U.S. dollar is the world's primary reserve currency.

The New York Stock Exchange on Wall Street is the world's largest stock exchange (per market capitalization of its listed companies) at $23.1 trillion as of April 2018.

In 2009, the private sector was estimated to constitute 86.4% of the economy. While its economy has reached a postindustrial level of development, the United States remains an industrial power. Consumer spending comprised 68% of the U.S. economy in 2015. In August 2010, the American labor force consisted of 154.1 million people (50%). With 21.2 million people, government is the leading field of employment. The largest private employment sector is health care and social assistance, with 16.4 million people. It has a smaller welfare state and redistributes less income through government action than most European nations.

The United States is the only advanced economy that does not guarantee its workers paid vacation and is one of a few countries in the world without paid family leave as a legal right. While federal law does not require sick leave, it is a common benefit for government workers and full-time employees at corporations. 74% of full-time American workers get paid sick leave, according to the Bureau of Labor Statistics, although only 24% of part-time workers get the same benefits. In 2009, the United States had the third-highest workforce productivity per person in the world, behind Luxembourg and Norway. It was fourth in productivity per hour, behind those two countries and the Netherlands.

Science and technology

Main articles: Science and technology in the United States and Science policy of the United States

Buzz Aldrin on the Moon, 1969

The United States has been a leader in technological innovation since the late 19th century and scientific research since the mid-20th century. Methods for producing interchangeable parts were developed by the U.S. War Department by the Federal Armories during the first half of the 19th century. This technology, along with the establishment of a machine tool industry, enabled the U.S. to have large-scale manufacturing of sewing machines, bicycles, and other items in the late 19th century and became known as the American system of manufacturing. Factory electrification in the early 20th century and introduction of the assembly line and other labor-saving techniques created the system of mass production. In the 21st century, approximately two-thirds of research and development funding comes from the private sector. The United States leads the world in scientific research papers and impact factor.

In 1876, Alexander Graham Bell was awarded the first U.S. patent for the telephone. Thomas Edison's research laboratory, one of the first of its kind, developed the phonograph, the first long-lasting light bulb, and the first viable movie camera. The latter led to emergence of the worldwide entertainment industry. In the early 20th century, the automobile companies of Ransom E. Olds and Henry Ford popularized the assembly line. The Wright brothers, in 1903, made the first sustained and controlled heavier-than-air powered flight.

The rise of fascism and Nazism in the 1920s and 30s led many European scientists, including Albert Einstein, Enrico Fermi, and John von Neumann, to immigrate to the United States. During World War II, the Manhattan Project developed nuclear weapons, ushering in the Atomic Age, while the Space Race produced rapid advances in rocketry, materials science, and aeronautics.

The invention of the transistor in the 1950s, a key active component in practically all modern electronics, led to many technological developments and a significant expansion of the U.S. technology industry. This, in turn, led to the establishment of many new technology companies and regions around the country such as Silicon Valley in California. Advancements by American microprocessor companies such as Advanced Micro Devices (AMD), and Intel along with both computer software and hardware companies that include Adobe Systems, Apple Inc., IBM, Microsoft, and Sun Microsystems created and popularized the personal computer. The ARPANET was developed in the 1960s to meet Defense Department requirements, and became the first of a series of networks which evolved into the Internet.

Income, poverty and wealth

Further information: Income in the United States, Poverty in the United States, Affluence in the United States, United States counties by per capita income, and Income inequality in the United States

Accounting for 4.24% of the global population, Americans collectively possess 29.4% of the world's total wealth, and Americans make up roughly half of the world's population of millionaires. The Global Food Security Index ranked the U.S. number one for food affordability and overall food security in March 2013. Americans on average have more than twice as much living space per dwelling and per person as European Union residents, and more than every EU nation. For 2017 the United Nations Development Programme ranked the United States 13th among 189 countries in its Human Development Index and 25th among 151 countries in its inequality-adjusted HDI (IHDI).

Wealth, like income and taxes, is highly concentrated; the richest 10% of the adult population possess 72% of the country's household wealth, while the bottom half claim only 2%. According to a September 2017 report by the Federal Reserve, the top 1% controlled 38.6% of the country's wealth in 2016. According to a 2018 study by the OECD, the United States has a larger percentage of low-income workers than almost any other developed nation. This is largely because at-risk workers get almost no government support and are further set back by a very weak collective bargaining system. The top one percent of income-earners accounted for 52 percent of the income gains from 2009 to 2015, where income is defined as market income excluding government transfers. In 2018, U.S. income inequality reached the highest level ever recorded by the Census Bureau.

Wealth inequality in the U.S. increased between 1989 and 2013.

After years of stagnation, median household income reached a record high in 2016 following two consecutive years of record growth. Income inequality remains at record highs however, with the top fifth of earners taking home more than half of all overall income. The rise in the share of total annual income received by the top one percent, which has more than doubled from nine percent in 1976 to 20 percent in 2011, has significantly affected income inequality, leaving the United States with one of the widest income distributions among OECD nations. The extent and relevance of income inequality is a matter of debate.

Between June 2007 and November 2008, the global recession led to falling asset prices around the world. Assets owned by Americans lost about a quarter of their value. Since peaking in the second quarter of 2007, household wealth was down $14 trillion, but has since increased $14 trillion over 2006 levels. At the end of 2014, household debt amounted to $11.8 trillion, down from $13.8 trillion at the end of 2008.

There were about 578,424 sheltered and unsheltered homeless persons in the US in January 2014, with almost two-thirds staying in an emergency shelter or transitional housing program. In 2011, 16.7 million children lived in food-insecure households, about 35% more than 2007 levels, though only 1.1% of U.S. children, or 845,000, saw reduced food intake or disrupted eating patterns at some point during the year, and most cases were not chronic. As of June 2018, 40 million people, roughly 12.7% of the U.S. population, were living in poverty, with 18.5 million of those living in deep poverty (a family income below one-half of the poverty threshold) and over five million live "in 'Third World' conditions." In 2016, 13.3 million children were living in poverty, which made up 32.6% of the impoverished population. In 2017, the U.S. state or territory with the lowest poverty rate was New Hampshire (7.6%), and the one with the highest was American Samoa (65%).

Infrastructure

Transportation

Main article: Transportation in the United States

The Interstate Highway System, which extends 46,876 miles (75,440 km)

Personal transportation is dominated by automobiles, which operate on a network of Template:Convert/e6mi of public roads. The United States has the world's second-largest automobile market, and has the highest rate of per-capita vehicle ownership in the world, with 765 vehicles per 1,000 Americans (1996).Template:Needs update In 2017, there were 255,009,283 non-two wheel motor vehicles, or about 910 vehicles per 1,000 people.

The civil airline industry is entirely privately owned and has been largely deregulated since 1978, while most major airports are publicly owned. The three largest airlines in the world by passengers carried are US-based; American Airlines is number one after its 2013 acquisition by US Airways. Of the world's 50 busiest passenger airports, 16 are in the United States, including the busiest, Hartsfield–Jackson Atlanta International Airport.

Energy

Further information: Energy policy of the United States

The United States energy market is about 29,000 terawatt hours per year. In 2005, 40% of this energy came from petroleum, 23% from coal, and 22% from natural gas. The remainder was supplied by nuclear and renewable energy sources.

Since 2007, the total greenhouse gas emissions by the United States are the second highest by country, exceeded only by China. The United States has historically been the world's largest producer of greenhouse gases, and greenhouse gas emissions per capita remain high.

See also

• Index of United States-related articles
• Lists of U.S. state topics
• Outline of the United States

Further reading

• Acharya, Viral V.; Cooley, Thomas F.; Richardson, Matthew P.; Walter, Ingo (2010). Regulating Wall Street: The Dodd-Frank Act and the New Architecture of Global Finance. Wiley. p. 592. ISBN 978-0-470-76877-8. 
• Baptist, Edward E. (2014). The Half Has Never Been Told: Slavery and the Making of American Capitalism. Basic Books. ISBN 978-0-465-00296-2. 
• (2010) "US Enacts Sweeping Financial Reform Legislation". Journal of Financial Economic Policy 2 (3): 192–195. DOI:10.1108/17576381011085412. 
• Berkin, Carol; Miller, Christopher L.; Cherny, Robert W.; Gormly, James L. (2007). Making America: A History of the United States, Volume I: To 1877. Cengage Learning. p. 75. ISBN 978-0-618-99485-4. https://books.google.com/books?id=cyEI21RClZkC. 
• (1992) "The Role of Epidemic Infectious Diseases in the Discovery of America". Allergy and Asthma Proceedings 13 (5): 225–232. DOI:10.2500/108854192778817040. PMID 1483570. 
• Blakeley, Ruth (2009). State Terrorism and Neoliberalism: The North in the South. Routledge. ISBN 978-0-415-68617-4. http://www.routledge.com/books/details/9780415462402/. 
• Boyer, Paul S.; Clark Jr., Clifford E.; Kett, Joseph F.; Salisbury, Neal; Sitkoff, Harvard; Woloch, Nancy (2007). The Enduring Vision: A History of the American People. Cengage Learning. p. 588. ISBN 978-0-618-80161-9. https://books.google.com/books?id=9KT3lI76-0cC. 
• Brokenshire, Brad (1993). Washington State Place Names. Caxton Press. p. 49. ISBN 978-0-87004-562-2. https://archive.org/details/washingtonstatep00brok_0. 
• Calloway, Colin G. (1998). New Worlds for All: Indians, Europeans, and the Remaking of Early America. JHU Press. p. 229. ISBN 978-0-8018-5959-5. https://books.google.com/books?id=edYbAZ7ECEoC. 
• Cobarrubias, Juan (1983). Progress in Language Planning: International Perspectives. Walter de Gruyter. ISBN 978-90-279-3358-4. https://books.google.com/books?id=x9KoAkzfVqIC&pg=PA195. 
• Cowper, Marcus (2011). National Geographic History Book: An Interactive Journey. National Geographic Society. ISBN 978-1-4262-0679-5. https://books.google.com/books?id=J8dNX2PqOpcC&pg=PT67. 
• Davis, Kenneth C. (1996). Don't know much about the Civil War. New York: William Marrow and Co.. p. 518. ISBN 978-0-688-11814-3. https://archive.org/details/dontknowmuchabou00davi_1/page/518. 
• Daynes, Byron W.; Sussman, Glen (2010). White House Politics and the Environment: Franklin D. Roosevelt to George W. Bush. Texas A&M University Press. p. 320. ISBN 978-1-60344-254-1. OCLC 670419432. https://archive.org/details/whitehousepoliti0000dayn. "Presidential environmental policies, 1933–2009" 
• Erlandson, Jon M; Rick, Torben C; Vellanoweth, Rene L (2008). A Canyon Through Time: Archaeology, History, and Ecology of the Tecolote Canyon Area, Santa Barbara County. California: University of Utah Press. ISBN 978-0-87480-879-7. https://books.google.com/books?id=GeTv2lmb79UC&pg=PA19. 
• Fagan, Brian M. (2016). Ancient Lives: An Introduction to Archaeology and Prehistory. Routledge. ISBN 978-1-317-35027-9. https://books.google.com/books?id=_9lqCwAAQBAJ&pg=PA390. 
• Feldstein, Sylvan G.; Fabozzi, Frank J. (2011). The Handbook of Municipal Bonds. John Wiley & Sons. p. 1376. ISBN 978-1-118-04494-0. https://books.google.com/books?id=Juc4fb1Fx1cC. 
• (1986) "The Myth of America's Turn to the Right". The Atlantic 257 (5): 43–53. Retrieved on March 11, 2013. 
• (2017) "Routes: Alternate Migration Corridors for Early Man in North America". American Antiquity 44 (1): 55–69. DOI:10.2307/279189. ISSN 0002-7316. 
• Flannery, Tim (2015). The Eternal Frontier: An Ecological History of North America and Its Peoples. Open Road + Grove/Atlantic. ISBN 978-0-8021-9109-0. https://books.google.com/books?id=mkkyBgAAQBAJ. 
• Fraser, Steve; Gerstle, Gary (1989). The Rise and Fall of the New Deal Order: 1930–1980. American History: Political science. Princeton University Press. p. 311. ISBN 978-0-691-00607-9. https://books.google.com/books?id=yd4GqkP5XYgC&lpg=PA229. 
• Gaddis, John Lewis (1972). The United States and the Origins of the Cold War, 1941–1947. Columbia University Press. ISBN 978-0-231-12239-9. 
• Gelo, Daniel J. (2018). Indians of the Great Plains. Taylor & Francis. ISBN 978-1-351-71812-7. https://books.google.com/books?id=KBBmDwAAQBAJ&pg=PT79. 
• Greg, Percy (1892). History of the United States from the Foundation of Virginia to the Reconstruction of the Union. West, Johnston & Company. p. 276. https://archive.org/details/historyofuniteds12greg. 
• García, Ofelia (2011). Bilingual Education in the 21st Century: A Global Perspective. John Wiley & Sons. ISBN 978-1-4443-5978-7. https://books.google.com/books?id=bW6V__K95ckC&pg=PT167. 
• Gold, Susan Dudley (2006). United States V. Amistad: Slave Ship Mutiny. Marshall Cavendish. p. 144. ISBN 978-0-7614-2143-6. https://archive.org/details/unitedstatesvami0000gold/page/144. 
• Gordon, John Steele (2004). An Empire of Wealth: The Epic History of American Economic Power. HarperCollins. ISBN 978-0-06-009362-4. https://archive.org/details/empireofwealthth00gord. 
• Graebner, Norman A.; Burns, Richard Dean; Siracusa, Joseph M. (2008). Reagan, Bush, Gorbachev: Revisiting the End of the Cold War. Praeger Security International Series. Greenwood Publishing Group. p. 180. ISBN 978-0-313-35241-6. https://books.google.com/books?id=r71u_AgE7iYC&lpg=PA142. 
• Haines, Michael Robert; Haines, Michael R.; Steckel, Richard H. (2000). A Population History of North America. Cambridge University Press. ISBN 978-0-521-49666-7. https://books.google.com/books?id=BPdgiysIVcgC&pg=PA12. 
• Haymes, Stephen; Vidal de Haymes, Maria; Miller, Reuben, eds (2014). The Routledge Handbook of Poverty in the United States. Routledge. ISBN 978-0-415-67344-0. http://www.routledge.com/books/details/9780415673440/. 
• Haviland, William A.; Walrath, Dana; Prins, Harald E.L. (2013). Evolution and Prehistory: The Human Challenge. Cengage Learning. ISBN 978-1-285-06141-2. https://books.google.com/books?id=9_qGhW338KQC&pg=PA219. 
• Hoopes, Townsend; Brinkley, Douglas (1997). FDR and the Creation of the U.N. Yale University Press. ISBN 978-0-300-08553-2. https://archive.org/details/fdrcreationofun00hoop. 
• Ingersoll, Thomas N. (2016). The Loyalist Problem in Revolutionary New England. Cambridge University Press. ISBN 978-1-107-12861-3. https://books.google.com/books?id=qwdQDQAAQBAJ&pg=PA208. 
• Inghilleri, Moira (2016). Translation and Migration. Taylor & Francis. ISBN 978-1-315-39980-5. https://books.google.com/books?id=h1yuDQAAQBAJ&pg=PT117. 
• Jacobs, Lawrence R. (2010). Health Care Reform and American Politics: What Everyone Needs to Know: What Everyone Needs to Know. Oxford University Press. ISBN 978-0-19-978142-3. https://archive.org/details/healthcarereform0000jaco. 
• Johnson, Paul (1997). A History of the American People. HarperCollins. ISBN 978-0-06-195213-5. https://books.google.com/books?id=RXSVQjz1_tMC. 
• Kurian, George T., ed (2001). Encyclopedia of American studies. New York: Grolier Educational. ISBN 978-0-7172-9222-6. OCLC 46343385. 
• Joseph, Paul (2016). The Sage Encyclopedia of War: Social Science Perspectives. Sage Publications. ISBN 978-1-4833-5988-5. https://books.google.com/books?id=idw0DQAAQBAJ&pg=PA590. 
• Kessel, William B.; Wooster, Robert (2005). Encyclopedia of Native American Wars and Warfare. Facts on File library of American History. Infobase Publishing. p. 398. ISBN 978-0-8160-3337-9. https://books.google.com/books?id=laxSyAp89G4C. 
• Kidder, David S.; Oppenheim, Noah D. (2007). The Intellectual Devotional: American History: Revive Your Mind, Complete Your Education, and Converse Confidently about Our Nation's Past. Rodale. ISBN 978-1-59486-744-6. https://books.google.com/books?id=PF39tMiwmWcC&pg=PA91. 
• Kruse, Kevin M. (2015). One Nation Under God: How Corporate America Invented Christian America. Basic Books. ISBN 978-0-465-04949-3. https://archive.org/details/onenationundergo0000krus. 
• Leckie, Robert (1990). None died in vain: The Saga of the American Civil War. New York: Harper-Collins. p. 682. ISBN 978-0-06-016280-1. https://books.google.com/books?id=gvIeAAAAMAAJ. 
• Lockard, Craig (2010). Societies, Networks, and Transitions, Volume B: From 600 to 1750. Cengage Learning. ISBN 978-1-111-79083-7. https://books.google.com/books?id=k91sCgAAQBAJ&pg=PA315. 
• Martinez, Donna; Bordeaux, Jennifer L. Williams (2016). 50 Events That Shaped American Indian History: An Encyclopedia of the American Mosaic [2 volumes]. ABC-CLIO. ISBN 978-1-4408-3577-3. https://books.google.com/books?id=KnB1DQAAQBAJ&pg=PA19. 
• Martinez, Donna; Sage, Grace; Ono, Azusa (2016). Urban American Indians: Reclaiming Native Space: Reclaiming Native Space. ABC-CLIO. ISBN 978-1-4408-3208-6. https://books.google.com/books?id=2HjEDAAAQBAJ&pg=PA4. 
• Martone, Eric (2016). Italian Americans: The History and Culture of a People. ABC-CLIO. ISBN 978-1-61069-995-2. https://books.google.com/books?id=MHJ1DQAAQBAJ&pg=PA504. 
• Leffler, Melvyn P. (2010). "The emergence of an American grand strategy, 1945–1952". In Westad, Odd Arne (in en). The Cambridge History of the Cold War. 1: Origins. Cambridge: Cambridge University Press. pp. 67–89. ISBN 978-0-521-83719-4. OCLC 309835719. 
• Lemon, James T. (1987). "Colonial America in the 18th Century". In Mitchell, Robert D.; Groves, Paul A.. North America: the historical geography of a changing continent. Rowman & Littlefield. Archived from the original on January 23, 2013. http://cascourses.uoregon.edu/geog471/wp-content/uploads/2010/01/Lemon.pdf. 
• Lien, Arnold Johnson (1913). Studies in History, Economics, and Public Law. 54. New York: Columbia University. p. 604. https://books.google.com/books?id=UYpVAAAAYAAJ. 
• Weierman, Karen Woods (2005). One Nation, One Blood: Interracial Marriage In American Fiction, Scandal, And Law, 1820–1870. University of Massachusetts Press. p. 214. ISBN 978-1-55849-483-1. https://books.google.com/books?id=24mIQuLBuN8C&pg=PA44. 
• Levenstein, Harvey (2003). Revolution at the Table: The Transformation of the American Diet. Berkeley and Los Angeles: University of California Press. ISBN 978-0-520-23439-0. 
• (2007) "Interracial Marriage in Early America: Motivation and the Colonial Project". Michigan Journal of History (Fall). 
• Meltzer, David J. (2009). First Peoples in a New World: Colonizing Ice Age America. University of California Press. ISBN 978-0-520-94315-5. https://books.google.com/books?id=Rnc-bg2voI8C&pg=PA129. 
• The New York Times (2007). The New York Times Guide to Essential Knowledge: A Desk Reference for the Curious Mind (2nd ed.). St. Martin's Press. ISBN 978-0-312-37659-8. https://archive.org/details/newyorktimesguid00. 
• Mostert, Mary (2005). The Threat of Anarchy Leads to the Constitution of the United States. CTR Publishing, Inc.. ISBN 978-0-9753851-4-2. https://books.google.com/books?id=jntSQ-yn66AC&pg=PA18. 
• Onuf, Peter S. (2010). The Origins of the Federal Republic: Jurisdictional Controversies in the United States, 1775–1787. University of Pennsylvania Press. ISBN 978-0-8122-0038-6. https://books.google.com/books?id=WcUgLPqmfuYC. 
• Perdue, Theda; Green, Michael D (2005). The Columbia Guide to American Indians of the Southeast. Columbia University Press. ISBN 978-0-231-50602-1. https://books.google.com/books?id=-RBJCyp2bFIC&pg=PA40. 
• Price, David A. (2003). Love and Hate in Jamestown: John Smith, Pocahontas, and the Start of a New Nation. Random House. ISBN 978-0-307-42670-3. https://books.google.com/books?id=_EFbS_7fFcYC. 
• Quirk, Joel (2011). The Anti-Slavery Project: From the Slave Trade to Human Trafficking. University of Pennsylvania Press. p. 344. ISBN 978-0-8122-4333-8. https://books.google.com/books?id=qqxK4KlqKYMC. 
• Ranlet, Philip (1999). Vaughan, Alden T.. ed. New England Encounters: Indians and Euroamericans Ca. 1600–1850. North Eastern University Press. 
• Rausch, David A. (1994). Native American Voices. Grand Rapids: Baker Books. p. 180. ISBN 978-0-8010-7773-9. https://books.google.com/books?id=iyZMeGMgIgEC&vq=triangle. 
• Remini, Robert V. (2007). The House: The History of the House of Representatives. HarperCollins. ISBN 978-0-06-134111-3. https://books.google.com/books?id=CAM6J6IoQFQC. 
• Richter, Daniel K.; Merrell, James H., eds (2003). Beyond the covenant chain : the Iroquois and their neighbors in Indian North America, 1600–1800. University Park: Pennsylvania State University Press. ISBN 978-0-271-02299-4. OCLC 51306167. https://books.google.com/books?id=ZQnEwUaPAegC. 
• Ripper, Jason (2008). American Stories: To 1877. M.E. Sharpe. p. 299. ISBN 978-0-7656-2903-6. https://books.google.com/books?id=vX-fYvoAeHwC. 
• Russell, John Henderson (1913). The Free Negro in Virginia, 1619–1865. Johns Hopkins University. p. 196. https://archive.org/details/freenegroinvirg00russgoog. 
• Safire, William (2003). No Uncertain Terms: More Writing from the Popular "On Language" Column in The New York Times Magazine. Simon and Schuster. p. 199. ISBN 978-0-7432-4955-3. https://archive.org/details/nouncertainterms00safi. 
• Samuel, Bunford (1920). Secession and Constitutional Liberty: In which is Shown the Right of a Nation to Secede from a Compact of Federation and that Such Right is Necessary to Constitutional Liberty and a Surety of Union. Neale publishing Company. p. 323. https://archive.org/details/secessionandcon03samugoog. 
• Savage, Candace (2011). Prairie: A Natural History. Greystone Books. ISBN 978-1-55365-899-3. https://books.google.com/books?id=X1u9BwAAQBAJ&pg=PA55. 
• Schneider, Dorothy; Schneider, Carl J. (2007). Slavery in America. Infobase Publishing. p. 554. ISBN 978-1-4381-0813-1. https://books.google.com/books?id=QlemwRTsY20C. 
• Schultz, David Andrew (2009). Encyclopedia of the United States Constitution. Infobase Publishing. p. 904. ISBN 978-1-4381-2677-7. https://books.google.com/books?id=f7m713xwK58C. 
• Sider, Sandra (2007). Handbook to Life in Renaissance Europe. Oxford University Press. ISBN 978-0-19-533084-7. https://books.google.com/books?id=JtYy67FsRosC&pg=PA226. 
• Simonson, Peter (2010). Refiguring Mass Communication: A History. Urbana: University of Illinois Press. ISBN 978-0-252-07705-0. https://books.google.com/books?id=N6lrAmPlbvIC&pg=PA79. "He held high the Declaration of Independence, the Constitution, and the nation's unofficial motto, e pluribus unum, even as he was recoiling from the party system in which he had long participated." 
• Smith, Andrew F. (2004). The Oxford Encyclopedia of Food and Drink in America. New York: Oxford University Press. pp. 131–132. ISBN 978-0-19-515437-5. 
• Soss, Joe (2010). Hacker, Jacob S.; Mettler, Suzanne. eds. Remaking America: Democracy and Public Policy in an Age of Inequality. Russell Sage Foundation. ISBN 978-1-61044-694-5. https://books.google.com/books?id=JttyjBoyb3AC. 
• Stannard, David E. (1993). American Holocaust: The Conquest of the New World. New York: Oxford University Press. ISBN 978-0-19-508557-0. https://archive.org/details/americanholocaus00stan. 
• Tadman, Michael (2000). "The Demographic Cost of Sugar: Debates on Slave Societies and Natural Increase in the Americas". American Historical Review 105 (5): 1534–1575. DOI:10.2307/2652029. 
• Taylor, Alan (2002). Eric Foner. ed. American Colonies: The Settling of North America. New York: Penguin Books. ISBN 978-0-670-87282-4. https://archive.org/details/americancolonies00tayl_1. 
• Thornton, Russell (1987). American Indian Holocaust and Survival: A Population History Since 1492. Civilization of the American Indian. 186. University of Oklahoma Press. p. 49. ISBN 978-0-8061-2220-5. https://books.google.com/books?id=9iQYSQ9y60MC&lpg=PA49. 
• Thornton, Russell (1998). Studying Native America: Problems and Prospects. Univ of Wisconsin Press. ISBN 978-0-299-16064-7. https://books.google.com/books?id=_EA-UwvN_HUC&pg=PA34. 
• Vaughan, Alden T. (1999). New England Encounters: Indians and Euroamericans Ca. 1600–1850. North Eastern University Press. 
• Volo, James M.; Volo, Dorothy Denneen (2007). Family Life in Native America. ABC-CLIO. ISBN 978-0-313-33795-6. https://books.google.com/books?id=z_bc61ezj0cC&pg=PR11. 
• Walton, Gary M.; Rockoff, Hugh (2009). History of the American Economy. Cengage Learning. ISBN 978-0-324-78662-0. https://books.google.com/books?id=lyhI1q_E4G0C. 
• (2007) "Redefining the Age of Clovis: Implications for the Peopling of the Americas". Science 315 (5815): 1122–1126. DOI:10.1126/science.1137166. ISSN 0036-8075. PMID 17322060. 
• Weiss, Edith Brown; Jacobson, Harold Karan (2000). Engaging Countries: Strengthening Compliance with International Environmental Accords. MIT Press. ISBN 978-0-262-73132-4. https://books.google.com/books?id=W_JAw31U5qQC&pg=PA180. 
• (2012) "Questioning Conservatism's Ascendancy: A Reexamination of the Rightward Shift in Modern American Politics; {Reviews in American History}". Reviews in American History 40 (2): 325–331. DOI:10.1353/rah.2012.0043. Retrieved on March 11, 2013. 
• Wilson, Wendy S.; Thompson, Lloyd M. (1997). Native Americans: An Interdisciplinary Unit on Converging Cultures. Walch Publishing. ISBN 978-0-8251-3332-9. https://books.google.com/books?id=Hs0HFU2ZR0IC&pg=PA14. 
• Winchester, Simon (2013). The men who United the States. Harper Collins. pp. 198, 216, 251, 253. ISBN 978-0-06-207960-2. https://archive.org/details/isbn_9780062079602. 
• Zinn, Howard (2005). A People's History of the United States. Harper Perennial Modern Classics. ISBN 978-0-06-083865-2. 

Internet sources

• "Country Profile: United States of America". BBC News (London). April 22, 2008. http://news.bbc.co.uk/2/hi/americas/country_profiles/1217752.stm. Retrieved May 18, 2008. 
• Cohen, Eliot A. (July–August 2004). "History and the Hyperpower". Washington, DC. http://www.foreignaffairs.com/articles/59919/eliot-a-cohen/history-and-the-hyperpower. Retrieved July 14, 2006. 
• "Slavery and the Slave Trade in Rhode Island". https://www.brown.edu/Facilities/John_Carter_Brown_Library/jcbexhibit/Pages/exhibSlavery.html. 
• "History of "In God We Trust"". U.S. Department of the Treasury. March 8, 2011. http://www.treasury.gov/about/education/Pages/in-god-we-trust.aspx. Retrieved February 23, 2013. 
• "Early History, Native Americans, and Early Settlers in Mercer County". Mercer County Historical Society. 2005. Archived from the original on March 10, 2005. https://web.archive.org/web/20050310021430/http://www.mchspa.org/body.htm. 
• Hayes, Nick (November 6, 2009). "Looking back 20 years: Who deserves credit for ending the Cold War?". MinnPost. http://www.minnpost.com/politics-policy/2009/11/looking-back-20-years-who-deserves-credit-ending-cold-war. Retrieved March 11, 2013. 
• "59e. The End of the Cold War". Independence Hall Association. http://www.ushistory.org/us/59e.asp. Retrieved March 10, 2013. 
• Levy, Peter B. (1996). Encyclopedia of the Reagan-Bush Years. ABC-CLIO. p. 442. ISBN 978-0-313-29018-3. https://books.google.com/books?id=7veohk0fkLYC&lpg=PA88. 
• "U.S. Census Bureau QuickFacts selected: United States". U.S. Census Bureau. 2016. https://www.census.gov/quickfacts/fact/table/US/PST045216. Retrieved September 9, 2017. 
• (2003) "Western Policy and the Demise of the Soviet Union". Journal of Cold War Studies 5 (4): 137–177. DOI:10.1162/152039703322483774. 
• (2014) "Testing Theories of American Politics: Elites, Interest Groups, and Average Citizens". Perspectives on Politics 12 (3): 564–581. DOI:10.1017/S1537592714001595. 

External links

	Definitions from Wiktionary
	Textbooks from Wikibooks
	Quotations from Wikiquote
	Source texts from Wikisource
	Images and media from Commons
	News stories from Wikinews
	Learning resources from Wikiversity

Library resources
About United States
Resources in your library Resources in other libraries

• CIA World Factbook entry on United States

• United States, from the BBC News
• Key Development Forecasts for the United States from International Futures

Government

• Official U.S. Government Web Portal Gateway to government sites
• House Official site of the United States House of Representatives
• Senate Official site of the United States Senate
• White House Official site of the president of the United States
• Supreme Court Official site of the Supreme Court of the United States

History

• Historical Documents Collected by the National Center for Public Policy Research
• U.S. National Mottos: History and Constitutionality Analysis by the Ontario Consultants on Religious Tolerance
• USA Collected links to historical data

Maps

• National Atlas of the United States Official maps from the U.S. Department of the Interior
• Wikimedia Atlas of the United States
• Measure of America A variety of mapped information relating to health, education, income, and demographics for the U.S.

Photos

• Photos of the USA