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 formed in 1827 out of Fayette County. It was named in honor of Isaac Shelby, governor of Kentucky and participant in the American Revolutionary War. Geography. According to the U.S. Census Bureau, the county has a total area of , of which is land and (1.2%) is water. Climate and weather. In recent years, average temperatures in the county seat of Shelbyville have ranged from a  low of in January to a high of in July, although a record low of was recorded in January 1915 and a record high of was recorded in July 1936. Average monthly precipitation ranged from in February to in June. 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 . There were 10,396 housing units at an average density of . 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. Communities. Townships. Shelby County is divided into these townships: