Pinckneyville is a city in and the county seat of Perry County, Illinois, United States. The population was 5,066 at the 2020 census. It is named for Charles Cotesworth Pinckney, an early American diplomat and presidential candidate. Pinckneyville is the location of the Pinckneyville Power Plant, a combustion turbine generator (CTG)-type power plant run by Ameren. Geography Pinckneyville is located on Illinois Route 13 about southeast of St. Louis. According to the 2010 census, Pinckneyville has a total area of , of which (or 93.63%) is land and (or 6.37%) is water. Demographics As of the census of 2000, there were 5,464 people, 1,504 households, and 920 families residing in the city. The population density was . There were 1,662 housing units at an average density of . The racial makeup of the city was 71.25% White, 24.36% African American, 0.16% Native American, 0.20% Asian, 0.05% Pacific Islander, 3.77% from other races, and 0.20% from two or more races. Hispanic or Latino of any race were 4.47% of the population. There were 1,504 households, out of which 25.6% had children under the age of 18 living with them, 47.3% were married couples living together, 11.3% had a female householder with no husband present, and 38.8% were non-families. 35.9% of all households were made up of individuals, and 18.8% had someone living alone who was 65 years of age or older. The average household size was 2.23 and the average family size was 2.90. In the city, the population was spread out, with 14.0% under the age of 18, 15.0% from 18 to 24, 39.7% from 25 to 44, 17.4% from 45 to 64, and 13.9% who were 65 years of age or older. The median age was 35 years. For every 100 females there were 188.3 males. For every 100 females age 18 and over, there were 209.9 males. The median income for a household in the city was $30,391, and the median income for a family was $41,574. Males had a median income of $23,402 versus $21,848 for females. The per capita income for the city was $15,601. About 8.2% of families and 11.0% of the population were below the poverty line, including 14.2% of those under age 18 and 12.1% of those age 65 or over. History Perry County was formed on January 29, 1827. It was named for Commodore Oliver H. Perry. When Perry County was established,