This article is based on the corresponding article in another wiki. For Familypedia purposes, it requires significantly more historical detail on phases of this location's development. The ideal article for a place will give the reader a feel for what it was like to live at that location at the time their relatives were alive there. Also desirable are links to organizations that may be repositories of genealogical information..
Please help to improve this page yourself if you can.

Piatt County, Illinois
Map of Illinois highlighting Piatt County
Location in the state of Illinois
Map of the U.S. highlighting Illinois
Illinois's location in the U.S.
Founded 1841
Seat Monticello
Largest city Monticello
 - Total
 - Land
 - Water

440 sq mi (1,140 km²)
440 sq mi (1,140 km²)
0 sq mi (<1 km²), 0.07%
 - (2000)
 - Density

37/sq mi (14/km²)
Time zone Central: UTC-6/-5

Piatt County is a county located in the U.S. state of Illinois. As of 2000, the population is 16,365. Its county seat is Monticello6.


According to the U.S. Census Bureau, the county has a total area of 1,140 km² (440 sq mi). 1,140 km² (440 sq mi) of it is land and 1 km² (0 sq mi) of it (0.07%) is water.

Adjacent Counties[]


Piatt County Illinois Courthouse in Monticello.

Piatt County was formed in 1841 from Macon and Dewitt Counties. It was named after James A. Piatt, a local resident instrumental in formation of the county.

Illinois Power Company was a major electric utility in Central Illinois, centered in Decatur, to the west of Piatt County. At one time, Illinois had a "personal property tax", an ad valorem tax levied by the counties on property that was not real estate. The personal property tax was a major expense for the electric utilities, since their generators and transmission lines were "personal property". Under Illinois law, a corporation, such as Illinois Power, paid personal property tax to the county in which the corporate headquarters was located. Because Piatt County offered a low tax rate, Illinois Power moved its corporate headquarters to that county. This allowed Piatt County to tax utility assets over half of the State, providing a rich source of revenue which was responsible for much of the wealth of this tiny county.


Historical populations
Census Pop.
1900 17,706
1910 16,376 −7.5%
1920 15,714 −4.0%
1930 15,588 −0.8%
1940 14,659 −6.0%
1950 13,970 −4.7%
1960 14,960 7.1%
1970 15,509 3.7%
1980 16,581 6.9%
1990 15,548 −6.2%
2000 16,365 5.3%
IL Counties 1900-1990

As of the census2 of 2000, there were 16,365 people, 6,475 households, and 4,726 families residing in the county. The population density was 14/km² (37/sq mi). There were 6,798 housing units at an average density of 6/km² (15/sq mi). The racial makeup of the county was 98.83% White, 0.24% Black or African American, 0.08% Native American, 0.13% Asian, 0.02% Pacific Islander, 0.14% from other races, and 0.57% from two or more races. 0.62% of the population were Hispanic or Latino of any race.

There were 6,475 households out of which 32.60% had children under the age of 18 living with them, 63.30% were married couples living together, 6.80% had a female householder with no husband present, and 27.00% were non-families. 23.70% of all households were made up of individuals and 11.80% had someone living alone who was 65 years of age or older. The average household size was 2.50 and the average family size was 2.96.

In the county the population was spread out with 25.10% under the age of 18, 6.80% from 18 to 24, 27.60% from 25 to 44, 25.00% from 45 to 64, and 15.50% who were 65 years of age or older. The median age was 40 years. For every 100 females there were 95.40 males. For every 100 females age 18 and over, there were 91.90 males.

The median income for a household in the county was $45,752, and the median income for a family was $52,218. Males had a median income of $36,762 versus $23,606 for females. The per capita income for the county was $21,075. About 3.60% of families and 5.00% of the population were below the poverty line, including 4.80% of those under age 18 and 6.20% of those age 65 or over.

Cities, towns and villages[]

Map of Piatt County, Illinois.

Coordinates: 40°01′N 88°35′W / 40.01, -88.59

This page uses content from the English language Wikipedia. The original content was at Piatt 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.