# Shelby County, Illinois

Shelby County is a county located in the U.S. state of Illinois. According to the 2020 census, it had a population of 20,990. Its county seat is Shelbyville.

## History

Shelby County was established in 1827 out of Fayette County. It was named in honor of Isaac Shelby, governor of Kentucky and participant in the American Revolutionary War.
* Shelby county from the time of its creation to 1829, including a large tract of unorganized territory temporarily attached to it, whose precise border was not defined.
* Shelby County between 1829 and 1839
* Shelby County between 1839 and 1843
* Shelby County in 1843, reduced to its present borders

## Geography

According to the U.S. Census Bureau, the county has a total area of 768 square miles (1,990 km$^2$), of which 759 square miles (1,970 km$^2$) is land and 9.5 square miles (25 km$^2$) (1.2%) is water.

### Climate and weather

In recent years, average temperatures in the county seat of Shelbyville have ranged from a low of 19 °F (−7 °C) in January to a high of 87 °F (31 °C) in July, although a record low of −26 °F (−32 °C) was recorded in January 1915 and a record high of 111 °F (44 °C) was recorded in July 1936. Average monthly precipitation ranged from 1.89 inches (48 mm) in February to 4.05 inches (103 mm) in June.

### Major highways

* Interstate 57
* U.S. Highway 45
* U.S. Highway 51
* Illinois Route 16
* Illinois Route 32
* Illinois Route 128

### Adjacent counties

* Macon County - north
* Moultrie County - northeast
* Coles County - east
* Cumberland County - east
* Effingham County - south
* Fayette County - south
* Montgomery County - southwest
* Christian County - west

## Demographics

As of the 2010 United States census, there were 22,363 people, 9,216 households, and 6,376 families living in the county. The population density was 29.5 inhabitants per square mile (11.4/km$^2$). There were 10,396 housing units at an average density of 13.7 per square mile (5.3/km$^2$). The racial makeup of the county was 98.6% white, 0.3% Asian, 0.2% American Indian, 0.2% black or African American, 0.2% from other races, and 0.6% from two or more races. Those of Hispanic or Latino origin made up 0.8% of the population. In terms of ancestry, 25.5% were German, 9.9% were English, 9.8% were American, and 8.8% were Irish.
Of the 9,216 households, 29.2% had children under the age of 18 living with them, 57.1% were married couples living together, 8.0% had a female householder with no husband present, 30.8% were non-families, and 27.1% of all households were made up of individuals. The average household size was 2.40 and the average family size was 2.90. The median age was 43.5 years.
The median income for a household in the county was $44,627 and the median income for a family was $55,655. Males had a median income of $40,119 versus $27,860 for females. The per capita income for the county was $21,891. About 7.8% of families and 11.3% of the population were below the poverty line, including 16.7% of those under age 18 and 8.1% of those age 65 or over.

### Census-designated place

The Census Bureau has defined one census-designated place (CDP) in Shelby County.
* Westervelt

## Government
### Townships

Shelby County is divided into these townships:
* Ash Grove
* Big Spring
* Clarksburg
* Cold Spring
* Dry Point
* Flat Branch
* Herrick
* Holland
* Lakewood
* Moweaqua
* Oconee
* Okaw
* Penn
* Pickaway
* Prairie
* Richland
* Ridge
* Rose
* Rural
* Shelbyville
* Sigel
* Todds Point
* Tower Hill
* Windsor

## Communities
### Cities

* Shelbyville (seat)
* Windsor

### Town

* Sigel

### Villages

* Cowden
* Findlay
* Herrick
* Moweaqua
* Oconee
* Stewardson
* Strasburg
* Tower Hill

### Other unincorporated communities

* Clarksburg
* Henton
* Lakewood
* Mode

## Politics

United States presidential election results for Shelby County, Illinois :
| Year | Republican | Republican | Democratic | Democratic | Third party(ies) | Third party(ies) |
| Year | No. | % | No. | % | No. | % |
| 2024 | 9,267 | 79.18% | 2,240 | 19.14% | 196 | 1.67% |
| 2020 | 9,426 | 77.80% | 2,504 | 20.67% | 185 | 1.53% |
| 2016 | 8,229 | 74.48% | 2,288 | 20.71% | 532 | 4.81% |
| 2012 | 6,843 | 65.55% | 3,342 | 32.01% | 254 | 2.43% |
| 2008 | 6,396 | 58.67% | 4,245 | 38.94% | 261 | 2.39% |
| 2004 | 6,753 | 63.85% | 3,744 | 35.40% | 80 | 0.76% |
| 2000 | 5,851 | 57.57% | 4,018 | 39.54% | 294 | 2.89% |
| 1996 | 4,215 | 43.06% | 4,249 | 43.41% | 1,324 | 13.53% |
| 1992 | 3,631 | 32.49% | 5,101 | 45.65% | 2,443 | 21.86% |
| 1988 | 5,370 | 53.28% | 4,650 | 46.14% | 58 | 0.58% |
| 1984 | 6,372 | 59.38% | 4,317 | 40.23% | 41 | 0.38% |
| 1980 | 6,441 | 59.12% | 3,988 | 36.61% | 465 | 4.27% |
| 1976 | 5,234 | 45.54% | 6,172 | 53.70% | 87 | 0.76% |
| 1972 | 7,217 | 62.08% | 4,389 | 37.75% | 20 | 0.17% |
| 1968 | 5,487 | 49.27% | 4,528 | 40.66% | 1,122 | 10.07% |
| 1964 | 4,281 | 37.66% | 7,088 | 62.34% | 0 | 0.00% |
| 1960 | 6,872 | 54.53% | 5,720 | 45.39% | 11 | 0.09% |
| 1956 | 7,075 | 56.94% | 5,337 | 42.95% | 13 | 0.10% |
| 1952 | 7,189 | 57.65% | 5,268 | 42.25% | 12 | 0.10% |
| 1948 | 5,282 | 47.89% | 5,589 | 50.68% | 158 | 1.43% |
| 1944 | 6,201 | 50.65% | 5,919 | 48.35% | 123 | 1.00% |
| 1940 | 7,250 | 47.71% | 7,704 | 50.69% | 243 | 1.60% |
| 1936 | 5,795 | 40.81% | 8,186 | 57.64% | 220 | 1.55% |
| 1932 | 4,657 | 35.91% | 8,093 | 62.40% | 219 | 1.69% |
| 1928 | 7,214 | 62.58% | 4,071 | 35.31% | 243 | 2.11% |
| 1924 | 5,605 | 48.13% | 5,265 | 45.21% | 776 | 6.66% |
| 1920 | 6,351 | 53.93% | 5,113 | 43.42% | 312 | 2.65% |
| 1916 | 5,911 | 42.61% | 7,515 | 54.18% | 445 | 3.21% |
| 1912 | 1,431 | 20.77% | 3,467 | 50.33% | 1,991 | 28.90% |
| 1908 | 3,312 | 42.30% | 4,065 | 51.92% | 453 | 5.79% |
| 1904 | 3,220 | 46.53% | 2,962 | 42.80% | 738 | 10.66% |
| 1900 | 3,365 | 41.38% | 4,514 | 55.52% | 252 | 3.10% |
| 1896 | 3,071 | 38.75% | 4,709 | 59.42% | 145 | 1.83% |
| 1892 | 2,304 | 32.45% | 3,523 | 49.62% | 1,273 | 17.93% |