# Piatt County, Illinois

Piatt County is a county in Illinois. According to the 2020 United States census, it had a population of 16,673. Its county seat is Monticello.
Piatt County is part of the Champaign-Urbana Metropolitan Area.

## History

The first settler was George Haworth, a Quaker, followed by James Martin, Abraham Hanline, Solomon Carter and William Cordell.
Piatt County was formed in 1841 from Macon and DeWitt counties. Two local residents, James A. Piatt and Jesse Warner, were instrumental in forming the county. It was named after James A. Piatt after winning a coin flip against Jesse Warner.
* Piatt County at the time of its creation in 1841
Abraham Lincoln practiced law in Piatt County as a circuit lawyer. Lincoln and Stephen A. Douglas planned their presidential debates in Piatt County in 1858, one of which is ornamented by a marker just south of Monticello.
The first courthouse was built in 1843. It was replaced by the current courthouse in 1904.

## Geography

According to the US Census Bureau, the county has a total area of 439 square miles (1,140 km$^2$), of which 439 square miles (1,140 km$^2$) is land and 0.3 square miles (0.78 km$^2$) (0.06%) is water.

### Climate and weather

In recent years, average temperatures in the county seat of Monticello have ranged from a low of 14 °F (−10 °C) in January to a high of 85 °F (29 °C) in July, although a record low of −25 °F (−32 °C) was recorded in January 1999 and a record high of 105 °F (41 °C) was recorded in July 1966. Average monthly precipitation ranged from 1.61 inches (41 mm) in January to 3.99 inches (101 mm) in August.

### Major highways

* Interstate 72
* Interstate 74
* U.S. Route 36
* U.S. Route 150
* Illinois Route 10
* Illinois Route 32
* Illinois Route 48
* Illinois Route 105

### Adjacent counties

* McLean County - north
* Champaign County - east
* Douglas County - southeast
* Moultrie County - south
* Macon County - southwest
* De Witt County - west

## Demographics

As of the 2010 United States Census, there were 16,729 people, 6,782 households, and 4,823 families residing in the county. The population density was 38.1 inhabitants per square mile (14.7/km$^2$). There were 7,269 housing units at an average density of 16.6 per square mile (6.4/km$^2$). The racial makeup of the county was 98.0% white, 0.3% black or African American, 0.3% Asian, 0.2% American Indian, 0.2% from other races, and 0.9% from two or more races. Those of Hispanic or Latino origin made up 1.0% of the population. In terms of ancestry, 26.1% were German, 21.9% were American, 15.2% were English, and 13.4% were Irish.
Of the 6,782 households, 32.0% had children under the age of 18 living with them, 59.4% were married couples living together, 8.0% had a female householder with no husband present, 28.9% were non-families, and 24.5% of all households were made up of individuals. The average household size was 2.46 and the average family size was 2.92. The median age was 42.6 years.
The median income for a household in the county was $55,752 and the median income for a family was $65,850. Males had a median income of $50,425 versus $32,304 for females. The per capita income for the county was $26,492. About 5.1% of families and 7.6% of the population were below the poverty line, including 10.8% of those under age 18 and 4.5% of those age 65 or over.

## Communities
### City

* Monticello (seat)

### Villages

* Atwood (partial)
* Bement
* Cerro Gordo
* Cisco
* De Land
* Hammond
* Mansfield

### Census-designated places

* La Place
* White Heath

### Other unincorporated communities

* Amenia
* Galesville
* Lodge
* Milmine
* Pierson
* Voorhies

### Former places

* Blue Ridge

### Townships

* Bement
* Blue Ridge
* Cerro Gordo
* Goose Creek
* Monticello
* Sangamon
* Unity
* Willow Branch

## Politics

United States presidential election results for Piatt County, Illinois :
| Year | Republican | Republican | Democratic | Democratic | Third party(ies) | Third party(ies) |
| Year | No. | % | No. | % | No. | % |
| 2024 | 6,104 | 63.94% | 3,204 | 33.56% | 238 | 2.49% |
| 2020 | 6,248 | 63.43% | 3,329 | 33.79% | 274 | 2.78% |
| 2016 | 5,634 | 62.19% | 2,645 | 29.19% | 781 | 8.62% |
| 2012 | 5,413 | 61.92% | 3,090 | 35.35% | 239 | 2.73% |
| 2008 | 4,991 | 55.34% | 3,859 | 42.79% | 168 | 1.86% |
| 2004 | 5,392 | 62.80% | 3,124 | 36.38% | 70 | 0.82% |
| 2000 | 4,619 | 55.09% | 3,488 | 41.60% | 278 | 3.32% |
| 1996 | 3,265 | 44.05% | 3,274 | 44.17% | 873 | 11.78% |
| 1992 | 3,076 | 36.42% | 3,520 | 41.67% | 1,851 | 21.91% |
| 1988 | 4,137 | 56.85% | 3,099 | 42.59% | 41 | 0.56% |
| 1984 | 5,000 | 63.46% | 2,840 | 36.05% | 39 | 0.49% |
| 1980 | 4,867 | 62.25% | 2,421 | 30.97% | 530 | 6.78% |
| 1976 | 4,442 | 55.39% | 3,509 | 43.75% | 69 | 0.86% |
| 1972 | 5,057 | 67.72% | 2,394 | 32.06% | 17 | 0.23% |
| 1968 | 3,973 | 56.28% | 2,447 | 34.66% | 639 | 9.05% |
| 1964 | 3,141 | 44.63% | 3,897 | 55.37% | 0 | 0.00% |
| 1960 | 4,506 | 60.90% | 2,889 | 39.05% | 4 | 0.05% |
| 1956 | 4,622 | 66.23% | 2,356 | 33.76% | 1 | 0.01% |
| 1952 | 4,701 | 67.82% | 2,220 | 32.03% | 11 | 0.16% |
| 1948 | 3,646 | 60.13% | 2,361 | 38.93% | 57 | 0.94% |
| 1944 | 3,912 | 59.38% | 2,641 | 40.09% | 35 | 0.53% |
| 1940 | 4,564 | 55.94% | 3,564 | 43.68% | 31 | 0.38% |
| 1936 | 3,931 | 48.77% | 4,084 | 50.66% | 46 | 0.57% |
| 1932 | 3,179 | 42.71% | 4,200 | 56.43% | 64 | 0.86% |
| 1928 | 4,565 | 69.62% | 1,959 | 29.88% | 33 | 0.50% |
| 1924 | 3,799 | 64.31% | 1,733 | 29.34% | 375 | 6.35% |
| 1920 | 4,283 | 68.16% | 1,903 | 30.28% | 98 | 1.56% |
| 1916 | 4,012 | 55.49% | 3,028 | 41.88% | 190 | 2.63% |
| 1912 | 1,150 | 30.71% | 1,417 | 37.84% | 1,178 | 31.46% |
| 1908 | 2,349 | 57.96% | 1,530 | 37.75% | 174 | 4.29% |
| 1904 | 2,515 | 63.24% | 1,334 | 33.54% | 128 | 3.22% |
| 1900 | 2,648 | 57.32% | 1,905 | 41.23% | 67 | 1.45% |
| 1896 | 2,579 | 56.07% | 1,958 | 42.57% | 63 | 1.37% |
| 1892 | 2,138 | 51.08% | 1,896 | 45.29% | 152 | 3.63% |