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McHenry County, Illinois
Seal of McHenry County, Illinois
Map of Illinois highlighting McHenry County
Location in the state of Illinois
Map of the U.S. highlighting Illinois
Illinois's location in the U.S.
Founded 1836
Seat Woodstock
Largest city Crystal Lake, Illinois - 42,000
 - Total
 - Land
 - Water

611.13 sq mi (1,583 km²)
603.51 sq mi (1,563 km²)
7.62 sq mi (20 km²), 1.25%
 - (2020)
 - Density

430/sq mi (166/km²)

McHenry County is a county located in the U.S. state of Illinois. As of 2020, the population was 310,229. Its county seat is Woodstock, Illinois[1]. This county is part of the Chicago metropolitan area. It is the sixth largest county, in terms of population, in the state of Illinois. Long known as a center of agriculture and recreation, it has more recently experienced rapid rates of suburbanization and urbanization.


According to the 2000 census, the county has a total area of 611.13 square miles (1,582.8 km2), of which 603.51 square miles (1,563.1 km2) (or 98.75%) is land and 7.62 square miles (19.7 km2) (or 1.25%) is water.[2]

Major highways[]

  • I-90.svg Interstate 90
  • US 12.svg U.S. Highway 12
  • US 14.svg U.S. Highway 14
  • US 20.svg U.S. Highway 20
  • Illinois 23.svg Illinois Route 23
  • Illinois 31.svg Illinois Route 31
  • Illinois 47.svg Illinois Route 47
  • Illinois 62.svg Illinois Route 62
  • Illinois 120.svg Illinois Route 120
  • Illinois 173.svg Illinois Route 173
  • Illinois 176.svg Illinois Route 176

Adjacent counties[]


McHenry County was formed in 1836 out of Cook and LaSalle Counties. The County was named for Major William McHenry, an Indian fighter who died in Vandalia in 1835.

McHenry County originally stretched all the way east to Lake Michigan, with the county seat centrally in McHenry, but in 1839, the eastern townships of the county were carved out to form Lake County.

President Gerald Ford's mother Dorothy Ayer Gardner Ford and maternal grandfather Levi Addison Gardner and possibly his maternal grandmother Adele Augusta Ayer Gardner were born in the county (near Harvard, Illinois).

Historical Sites[]

  • The Count's House, 3803 Waukegan Rd, McHenry
  • Charles H. Hibbard House, 413 W Grant Hwy, Marengo
  • Orson Rogers House, 19621 E Grant Hwy, Marengo
  • Lucein Boneparte Covell House, 5805 Broadway, Richmond
  • Memorial Hall, 10308 Main St, Richmond
  • Old McHenry County Courthouse, Woodstock City Square, Woodstock
  • Woodstock Opera House, 110 Van Buren St, Woodstock
  • Woodstock Square Historic District, Woodstock
  • George Stickney House, 1904 Cherry Valley Rd, Bull Valley
  • Terwilliger House, Mason Hill Rd & Cherry Valley Rd, Bull Valley


Historical populations
Census Pop.
1840 2,578
1850 14,978 481.0%
1860 22,089 47.5%
1870 23,762 7.6%
1880 24,908 4.8%
1890 26,114 4.8%
1900 29,759 14.0%
1910 32,509 9.2%
1920 33,164 2.0%
1930 35,079 5.8%
1940 37,311 6.4%
1950 50,656 35.8%
1960 84,210 66.2%
1970 111,555 32.5%
1980 147,897 32.6%
1990 183,241 23.9%
2000 260,077 41.9%
2010 308,760 18.7%
IL Counties 1900-1990

As of the census[3] of 2000, there were 260,077 people, 89,403 households, and 69,287 families residing in the county. The population density was 431 people per square mile (166/km²). There were 92,908 housing units at an average density of 154 per square mile (59/km²). The racial makeup of the county was 93.91% White, 0.59% Black or African American, 0.17% Native American, 1.45% Asian, 0.02% Pacific Islander, 2.77% from other races, and 1.08% from two or more races. 7.54% of the population were Hispanic or Latino of any race. 28.5% were of German, 12.2% Irish, 9.8% Polish, 8.8% Italian and 5.6% English ancestry according to Census 2000. 89.3% spoke English, 6.4% Spanish and 1.0% Polish as their first language. The population of the Polish population has doubled within the last several years.

There were 89,403 households out of which 42.90% had children under the age of 18 living with them, 66.50% were married couples living together, 7.60% had a female householder with no husband present, and 22.50% were non-families. 18.00% of all households were made up of individuals and 6.10% had someone living alone who was 65 years of age or older. The average household size was 2.89 and the average family size was 3.31.

In the county the population was spread out with 30.20% under the age of 18, 7.10% from 18 to 24, 33.50% from 25 to 44, 21.30% from 45 to 64, and 8.00% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 100.70 males. For every 100 females age 18 and over, there were 98.00 males.

The median income for a household in the county was $64,826, and the median income for a family was $71,553. Males had a median income of $50,479 versus $31,141 for females. The per capita income for the county was $26,476. About 2.50% of families and 3.70% of the population were below the poverty line, including 3.80% of those under age 18 and 3.60% of those age 65 or over.

Climate and weather[]

Climate chart for Woodstock, Illinois
temperatures in °Cprecipitation totals in mm
source: The Weather Channel[4]

In recent years, average temperatures in the county seat of Woodstock have ranged from a low of 11 °F (−12 °C) in January to a high of 85 °F (29 °C) in July, although a record low of −29 °F (−33.9 °C) was recorded in January 1979 and a record high of 109 °F (43 °C) was recorded in July 1936. Average monthly precipitation ranged from 1.29 inches (33 mm) in February to 4.56 inches (116 mm) in June.[4]

McHenry County is like much of the Upper Midwest, as it usually sees hot, humid summers, and cold, snowy winters. The county is notably susceptible to high wind events, blizzards, severe thunderstorms, tornadoes, and flooding.

Some of the most notable weather events in the county include the 1965 Palm Sunday tornado outbreak, the Blizzard of 1967, the 1967 Belvidere - Oak Lawn tornado outbreak, the Blizzard of 1979, the Flood of 1996, the Blizzard of 1999, the Early Winter 2006 North American Storm Complex, the 2007 Midwest flooding event, the January 2008 tornado outbreak sequence, and the Blizzard of 2011.


McHenry County government is based primarily out of Woodstock, the county seat. The McHenry County Government Center, located on the north end of Woodstock along Illinois Route 47, features county offices as well as judicial facilities. Several state agencies also have local offices in Woodstock.


As a primarily outer suburban and exurban area, McHenry County has voted for the Republican candidate for President in all but two elections since 1880, the first being when “Bull Moose” candidate and former Republican president Theodore Roosevelt won the county in 1912.[5] Recent elections in 2004 and 2000 saw George W. Bush capture 59.72% and 58.5% of the county vote, respectively. In 2008, Democrat Barack Obama, then a Senator from Illinois, captured McHenry County with 52% of the vote—the first time a Democrat had carried the county since 1852. In the 2012 presidential election, Obama only received 44% of the vote whereas Republican Mitt Romney captured 53% of the vote.[6] In the 2016 presidential election, Republican Donald Trump received 50% of the vote whereas Democratic Hillary Clinton received 42% of the vote.

United States presidential election results for McHenry County, Illinois[7]
Year Republican Democratic Third party
No.  % No.  % No.  %
2020 82,260 49.98% 78,154 47.49% 4,164 2.53%
2016 71,612 49.75% 60,803 42.24% 11,515 8.00%
2012 71,598 53.34% 59,797 44.55% 2,842 2.12%
2008 64,845 46.44% 72,288 51.77% 2,499 1.79%
2004 76,412 59.72% 50,330 39.34% 1,206 0.94%
2000 62,112 58.49% 40,698 38.33% 3,375 3.18%
1996 41,136 49.41% 31,240 37.52% 10,880 13.07%
1992 41,356 46.84% 24,783 28.07% 22,155 25.09%
1988 46,135 70.44% 18,919 28.88% 445 0.68%
1984 47,282 76.21% 14,420 23.24% 340 0.55%
1980 40,045 64.95% 14,540 23.58% 7,070 11.47%
1976 37,115 67.50% 16,799 30.55% 1,075 1.95%
1972 36,114 74.75% 12,090 25.02% 108 0.22%
1968 27,245 66.15% 10,896 26.46% 3,044 7.39%
1964 22,503 55.54% 18,014 44.46% 0 0.00%
1960 25,787 66.97% 12,659 32.87% 62 0.16%
1956 24,912 78.34% 6,820 21.45% 66 0.21%
1952 20,975 74.23% 7,218 25.54% 64 0.23%
1948 15,387 73.45% 5,459 26.06% 103 0.49%
1944 15,666 73.55% 5,567 26.14% 66 0.31%
1940 16,480 72.30% 6,170 27.07% 145 0.64%
1936 12,031 60.56% 6,893 34.70% 942 4.74%
1932 9,880 53.14% 8,260 44.42% 454 2.44%
1928 10,661 65.33% 5,596 34.29% 62 0.38%
1924 8,751 67.24% 1,372 10.54% 2,892 22.22%
1920 9,885 85.10% 1,536 13.22% 195 1.68%
1916 9,024 72.00% 3,278 26.15% 231 1.84%
1912 2,370 31.82% 1,913 25.69% 3,164 42.49%
1908 5,331 71.07% 1,887 25.16% 283 3.77%
1904 5,409 77.21% 1,309 18.68% 288 4.11%
1900 5,234 70.09% 2,076 27.80% 158 2.12%
1896 5,047 70.91% 1,913 26.88% 157 2.21%
1892 3,205 55.16% 2,311 39.78% 294 5.06%


McHenry County College, a rapidly growing community college established in 1967, serves the majority of county residents. The college includes 2,000 full-time students and 5,800 part-time students. The main campus is located on the northwest side of Crystal Lake, along U.S. Route 14. Secondary facilities exist in Crystal Lake and McHenry.

McHenry County also includes dozens of school districts. There are also several high schools in the county. The largest high schools are McHenry High School East & West, Johnsburg High School, Woodstock High School, Woodstock North High School, Prairie Ridge High School, Crystal Lake Central High School, Crystal Lake South High School, Cary-Grove High School, Harry D. Jacobs High School, and Huntley High School, all of which are part of the Fox Valley Conference. Harvard High School, Richmond-Burton High School, and Marengo Community High School are part of the Big Northern Conference. Alden-Hebron High School, Faith Lutheran High School and Marian Central Catholic High School are also found in the county.

Medical facilities[]

McHenry County is gradually gaining a reputation as an important center of healthcare, due to its unique location and proximity to a wide range of hospital systems. Hospitals currently in the county include Mercy Harvard Hospital, Centegra Northern Illinois Medical Center in McHenry, and Centegra Memorial Medical Center in Woodstock. There are also plans to build a Centegra hospital in Huntley or Mercy hospital in Crystal Lake. Provena, Advocate, and Sherman also maintain a strong presence in the county, and have hospitals in nearby Elgin and Barrington.


Much of McHenry County's economy centers around manufacturing, metalworking, media development and printing, transportation equipment, agriculture, heathcare, education, retail, food production, distribution, and technology.

The major employment centers can be found in Crystal Lake, Algonquin, Huntley, McHenry, and Woodstock.

The southern portions of the county are within the scope of the Golden Corridor, the region of commerce along the Jane Addams Memorial Tollway.


The county is known for its wide variety of shopping options. McHenry, Crystal Lake, and Algonquin/Lake in the Hills have established themselves as major retail areas, all featuring an array of big box stores, specialty stores, and restaurants. While there are no major malls located within the county, several lie just outside its borders: the lifestyle centers Algonquin Commons and Algonquin Galleria, the Huntley Prime Outlets outlet mall, and the regional indoor mall Spring Hill Mall in West Dundee.

In addition, several historic downtowns throughout the county offer unique shops and eateries in charming environments. The Woodstock Square Historic District, antique shops in Richmond and Hebron, downtown Crystal Lake and downtown Algonquin, and shops in other historic downtowns throughout the county accommodate residents and tourists alike. McHenry's Green Street is also a major attraction in the county.


The entire county is served by the McHenry County Conservation District, which preserves sensitive land throughout the county and provides recreational opportunities for residents. The District also operates the McHenry County Prairie Path, a regional bike path that extends from the Wisconsin State Line in Richmond southward to Algonquin, where the path connects with the Fox River Bike Trail, which continues south to Aurora.

In addition, the Fox River and Chain O'Lakes provide immense opportunites for boating, fishing, swimming, and other water activities. Moraine Hills State Park and Chain O' Lakes State Park are both located in the county, adjacent to the waterway. Other major lakes in the county include Crystal Lake, Wonder Lake, and McCullom Lake.

There are also dozens of parks, golf courses, and country clubs throughout the county.

Major skiing areas include Nordic Ski Jump in Fox River Grove and Buffalo Snowboarding Park in Algonquin. In addition, the Windy City Balloon Port in Fox River Grove offers hot air balloon rides over the Fox River Valley.


McHenry County has an active art and theater scene. The historic Woodstock Opera House and Crystal Lake's Raue Center for the Arts both provide exceptional programs. In addition, Algonquin is noted for its Public Art Program, which showcases artwork year-round throughout the community. The county is also ideal for photography and filming. Much of the filming for the 1993 movie Groundhog Day took place in Woodstock.

There are also several important points of interest in the county including the Illinois Railway Museum and McHenry County Historical Museum in Union, the Old McHenry County Courthouse in Woodstock, and a variety of historical homes including the Orson Rogers House, George Stickney House, Charles H. Hibbard House, the Terwilliger House, the Count's House, and the Dole Mansion.

Throughout the year are a variety of festivals throughout the county, the centerpiece of which is the McHenry County Fair, occurring during a week in August in Woodstock. Many towns also have their own festivals throughout the year. Some of the most notable ones are the Ground Hog Days in Woodstock, Fall Fest in Huntley, the Summer Sunset Festival in Lake in the Hills, the Gala Festival in Crystal Lake, Milk Days in Harvard, Settler's Days in Marengo, Cary Days in Cary, Founders Days in Algonquin, and Fiesta Days in McHenry.


Several state highways run through McHenry County, including U.S. Route 20, U.S. Route 14, U.S. Route 12, Illinois Route 23, Illinois Route 173, Illinois Route 120, Illinois Route 176, Illinois Route 47, Illinois Route 31, and Illinois Route 62. Highly traveled county highways include Randall Road, Algonquin Road, and Walkup Road.

McHenry County is also the most populous county in the United States without direct access to an Interstate within its borders. As a result, most residents use nearby Interstate 90 (Jane Addams Memorial Tollway), a couple miles south in Kane County, to access the interstate highway system.

McHenry County is also served by Metra Rail, which provides daily commuter service to and from downtown Chicago. There are seven stations in the county, all of them located along the Union Pacific/Northwest Line. The county is also served by Pace, which provides three regular bus routes, and dial-a-ride service for several communities.

Lake in the Hills Airport offers general aviation service, as do Dacy Airport and Galt Airport, in the northern part of the county. Chicago-O'Hare International Airport is approximately 30–40 miles from the county, while Milwaukee's General Mitchell International Airport is approximately 50–60 miles. Chicago Rockford International Airport, a busy cargo airport with limited, scheduled passenger service is located approximately 42 miles west of the central part of the county (Woodstock).


McHenry County is entirely within the scope of the Chicago media market and the majority of the county relies primarily on Chicago television stations, radio stations, and newspapers for the source of its news and information. Certain sections of the county, particularly the rural far northern and far western parts, are also within the scope of the Milwaukee and Rockford media markets, respectively.

The county does have one FM radio station (WZSR - Star 105.5 FM), which plays mostly Adult Contemporary and pop music, and one AM radio station (WAIT - 850 AM). WZSR is based out of Woodstock, while WAIT is based out of Crystal Lake.

The Northwest Herald, with a circulation of almost 39,000, is the county's primary newspaper, serving the greater McHenry County area, and printed and published in Crystal Lake. The county is also served by the larger Chicago newspapers Chicago Tribune, Chicago Sun-Times, and the suburban-focused newspaper The Daily Herald. McHenry County Living, a bimonthly lifestyle magazine serving the county, also reaches tens of thousands of area residents and businesses. There are also several weekly publications throughout the county, focusing on the individual municipalities.


  • Alden
  • Algonquin
  • Burton
  • Chemung
  • Coral
  • Dorr
  • Dunham
  • Grafton
  • Greenwood

  • Hartland
  • Hebron
  • Marengo
  • McHenry
  • Nunda
  • Richmond
  • Riley
  • Seneca

Cities and villages[]

  • Crystal Lake (pop. 42,180)
  • Algonquin (pop. 30,347) - partly in Kane County
  • Lake in the Hills (pop. 29,704)
  • McHenry (pop. 27,165)
  • Woodstock (pop. 24,333)
  • Huntley (pop. 23,177) - partly in Kane County
  • Cary (pop. 19,641)
  • Fox Lake (pop. 11,042) - mostly in Lake County
  • Harvard (pop. 9,965)
  • Island Lake (pop. 8,617) - partly in Lake County
  • Marengo (pop. 7,614)
  • Johnsburg (pop. 6,806)
  • Spring Grove (pop. 5,807)
  • Lakemoor (pop. 5,776) - partly in Lake County
  • Fox River Grove (pop. 5,202) - partly in Lake County

  • Barrington Hills (pop. 4,375) - partly in Cook, Kane, and Lake Counties
  • Wonder Lake (pop. 3,867)
  • Lakewood (pop. 3,706)
  • Oakwood Hills (pop. 2,395)
  • Richmond (pop. 2,317)
  • Prairie Grove (pop. 2,007)
  • Hebron (pop. 1,426)
  • Bull Valley (pop. 1,129)
  • McCullom Lake (pop. 1,111)
  • Port Barrington (pop. 788) - partly in Lake County
  • Holiday Hills (pop. 716)
  • Union (pop. 620)
  • Trout Valley (pop. 601)
  • Ringwood (pop. 544)
  • Greenwood (pop. 257)

Census designated places[]

  • Wonder Lake (CDP) (pop. 7,463)
  • Pistakee Highlands (pop. 3,812)

Unincorporated communities[]

  • Alden
  • Big Foot Prairie (partial)
  • Burtons Bridge
  • Chemung
  • Coral
  • Franklinville

  • Harmony
  • Hartland
  • Lawrence
  • Ridgefield
  • Riley

  • Silver Lake
  • Solon Mills
  • Sunnyside

Notable residents[]

  • Alkaline Trio - Alternative/Punk rock band
  • Neil Michling - Actor/Writer/Director

See also[]

  • National Register of Historic Places listings in McHenry County, Illinois


  • Forstall, Richard L. (editor) (1996). Population of states and counties of the United States: 1790 to 1990 : from the twenty-one decennial censuses. United States Department of Commerce, Bureau of the Census, Population Division. ISBN 0-934213-48-8. 
  1. ^ "Find a County". National Association of Counties. Retrieved 2011-06-07. 
  2. ^ "Census 2000 U.S. Gazetteer Files: Counties". United States Census. Retrieved 2011-02-13. 
  3. ^ "American FactFinder". United States Census Bureau. Retrieved 2008-01-31. 
  4. ^ a b "Monthly Averages for Woodstock, Illinois". The Weather Channel. Retrieved 2011-01-27. 
  5. ^ Cite error: Invalid <ref> tag; no text was provided for refs named PGyard
  6. ^ "mcvote". 
  7. ^ Leip, David. "Dave Leip's Atlas of U.S. Presidential Elections". 

Further reading[]

  • Dupré, D.H. and D.M. Robertson. (2004). Water quality of Nippersink Creek and Wonder Lake, McHenry County, Illinois, 1994-2001 [Scientific Investigations Report 2004-5085]. Reston, VA: U.S. Department of the Interior, U.S. Geological Survey.

External links[]

Coordinates: 42°19′N 88°27′W / 42.32, -88.45

This page uses content from the English language Wikipedia. The original content was at McHenry County, Illinois. The list of authors can be seen in the page history. As with this Familypedia wiki, the content of Wikipedia is available under the Creative Commons License.