# Clinton County, Illinois

Clinton County is a county located in the U.S. state of Illinois. At the 2020 census, the population was 36,899. Its county seat is Carlyle. In 1960, the United States Census Bureau placed the mean center of U.S. population in Clinton County. Clinton County is part of the St. Louis, MO-IL Metropolitan Statistical Area.

## History

In 1805, prior to the establishment of the county, the territorial government established a post road from its capital (Vincennes, Indiana) to St. Louis, Missouri, passing through the county. In 1808 a wagon road was laid out through the future Clinton County. It extended from the Goshen Settlement to the Ohio salt works and crossed the Kaskaskia River at Carlyle. Clinton County became the home to early settlers by 1814, when the first land entries were made.
Clinton County was created on December 27, 1824, from portions of Washington, Fayette, and Bond Counties. It was named for the seventh Governor of New York, DeWitt Clinton, who helped build the Erie Canal.
Crossing the Kaskaskia became much easier when the bridge now known as the General Dean Suspension Bridge was built in 1859, at a cost of $40,000. Before the bridge was constructed, crossings involved a ferry or a mud bridge. The Illinois General Assembly set aside $20,000 for bridge restoration in 1951, and in 1953 the bridge was named after William F. Dean.

## Geography

According to the U.S. Census Bureau, the county has a total area of 503 square miles (1,300 km$^2$), of which 474 square miles (1,230 km$^2$) is land and 29 square miles (75 km$^2$) (5.8%) is water. Eldon Hazlet State Recreation Area and South Shore State Park are in Clinton County. Its southern border is the Kaskaskia River.

### Climate and weather

In recent years, average temperatures in the county seat of Carlyle have ranged from a low of 19 °F (−7 °C) in January to a high of 88 °F (31 °C) in July, although a record low of −22 °F (−30 °C) was recorded in January 1994 and a record high of 104 °F (40 °C) was recorded in July 1980. Average monthly precipitation ranged from 2.17 inches (55 mm) in January to 4.44 inches (113 mm) in June.

### Transit

* South Central Transit

### Major highways

* Interstate 64
* US Route 50
* Illinois Route 127
* Illinois Route 160
* Illinois Route 161
* Illinois Route 177

### Adjacent counties

* Bond County - north
* Fayette County - northeast
* Madison County - northwest
* Marion County - east
* St. Clair County - west
* Washington County - south

## Demographics

As of the 2010 United States census, there were 37,762 people, 14,005 households, and 9,760 families residing in the county. The population density was 79.7 inhabitants per square mile (30.8/km$^2$). There were 15,311 housing units at an average density of 32.3 per square mile (12.5/km$^2$). The racial makeup of the county was 93.4% white, 3.5% black or African American, 0.4% Asian, 0.2% American Indian, 1.2% from other races, and 1.1% from two or more races. Those of Hispanic or Latino origin made up 2.8% of the population. In terms of ancestry, 54.8% were German, 9.8% were Irish, 5.8% were English, and 5.6% were American.
Of the 14,005 households, 32.7% had children under the age of 18 living with them, 56.5% were married couples living together, 8.7% had a female householder with no husband present, 30.3% were non-families, and 25.1% of all households were made up of individuals. The average household size was 2.55 and the average family size was 3.02. The median age was 39.3 years.
The median income for a household in the county was $55,278 and the median income for a family was $66,682. Males had a median income of $45,119 versus $34,051 for females. The per capita income for the county was $25,392. About 5.2% of families and 7.8% of the population were below the poverty line, including 9.2% of those under age 18 and 5.7% of those age 65 or over.

## Education

* Carlyle Community Unit School District 1
* Patoka Community Unit School District 100
* Sandoval Community Unit School District 501
* Wesclin Community Unit School District 3
* Central Community High School, Breese
* Mater Dei Catholic High School, Breese

## Communities
### Cities

* Breese
* Carlyle
* Centralia (partial)
* Trenton
* Wamac (partial)

### Villages

* Albers
* Aviston
* Bartelso
* Beckemeyer
* Damiansville
* Germantown
* Hoffman
* Huey
* Keyesport (partial)
* New Baden (partial)
* Saint Rose

### Townships

* Breese
* Brookside
* Carlyle
* Clement
* Germantown
* Irishtown
* Lake
* Looking Glass
* Meridian
* Saint Rose
* Santa Fe
* Sugar Creek
* Wade
* Wheatfield

### Unincorporated Communities

* Boulder
* Ferrin
* Harbor Light Bay
* Jamestown
* Marydale
* New Memphis
* New Memphis Station
* North Harbor
* Panorama Hills
* Posey
* Royal Lake Resort
* Shattuc
* Snearlyille
* Stottletown
* Wertenberg

## Politics

As of February 2025, the county is one of 7 that voted to join the state of Indiana.
United States presidential election results for Clinton County, Illinois :
| Year | Republican | Republican | Democratic | Democratic | Third party(ies) | Third party(ies) |
| Year | No. | % | No. | % | No. | % |
| 2024 | 14,407 | 74.62% | 4,447 | 23.03% | 452 | 2.34% |
| 2020 | 14,304 | 74.45% | 4,493 | 23.38% | 417 | 2.17% |
| 2016 | 12,412 | 71.26% | 3,945 | 22.65% | 1,062 | 6.10% |
| 2012 | 10,524 | 63.86% | 5,596 | 33.95% | 361 | 2.19% |
| 2008 | 9,357 | 54.04% | 7,657 | 44.22% | 300 | 1.73% |
| 2004 | 10,219 | 59.65% | 6,797 | 39.68% | 115 | 0.67% |
| 2000 | 8,588 | 55.67% | 6,436 | 41.72% | 403 | 2.61% |
| 1996 | 6,065 | 43.81% | 6,104 | 44.09% | 1,675 | 12.10% |
| 1992 | 5,771 | 36.47% | 6,686 | 42.26% | 3,365 | 21.27% |
| 1988 | 7,681 | 56.15% | 5,935 | 43.38% | 64 | 0.47% |
| 1984 | 9,233 | 66.43% | 4,628 | 33.30% | 38 | 0.27% |
| 1980 | 8,500 | 62.53% | 4,470 | 32.88% | 623 | 4.58% |
| 1976 | 7,245 | 53.00% | 6,275 | 45.90% | 151 | 1.10% |
| 1972 | 7,931 | 62.39% | 4,756 | 37.41% | 25 | 0.20% |
| 1968 | 6,561 | 53.78% | 4,453 | 36.50% | 1,185 | 9.71% |
| 1964 | 4,692 | 39.00% | 7,339 | 61.00% | 0 | 0.00% |
| 1960 | 5,709 | 47.96% | 6,188 | 51.99% | 6 | 0.05% |
| 1956 | 7,378 | 63.46% | 4,242 | 36.48% | 7 | 0.06% |
| 1952 | 6,760 | 58.18% | 4,853 | 41.76% | 7 | 0.06% |
| 1948 | 5,128 | 51.47% | 4,773 | 47.91% | 62 | 0.62% |
| 1944 | 6,753 | 62.82% | 3,944 | 36.69% | 53 | 0.49% |
| 1940 | 7,582 | 62.00% | 4,558 | 37.27% | 90 | 0.74% |
| 1936 | 3,653 | 32.78% | 5,355 | 48.05% | 2,137 | 19.17% |
| 1932 | 2,548 | 24.35% | 7,736 | 73.92% | 182 | 1.74% |
| 1928 | 3,031 | 30.77% | 6,774 | 68.76% | 47 | 0.48% |
| 1924 | 2,358 | 29.69% | 1,693 | 21.32% | 3,891 | 48.99% |
| 1920 | 4,564 | 63.71% | 1,661 | 23.19% | 939 | 13.11% |
| 1916 | 3,423 | 42.59% | 4,201 | 52.27% | 413 | 5.14% |
| 1912 | 973 | 20.48% | 2,674 | 56.29% | 1,103 | 23.22% |
| 1908 | 2,104 | 39.11% | 3,016 | 56.06% | 260 | 4.83% |
| 1904 | 1,848 | 43.02% | 2,153 | 50.12% | 295 | 6.87% |
| 1900 | 1,964 | 41.60% | 2,637 | 55.86% | 120 | 2.54% |
| 1896 | 1,863 | 41.75% | 2,572 | 57.64% | 27 | 0.61% |
| 1892 | 1,361 | 34.68% | 2,393 | 60.97% | 171 | 4.36% |