Pinckneyville is a city in and the county seat of Perry County, Illinois, United States. The population was 5,648 at the 2010 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.
Pinckneyville is located on Illinois Route 13 about 60 miles (97 km) southeast of St. Louis.
According to the 2010 census, Pinckneyville has a total area of 4.315 square miles (11.18 km2), of which 4.04 square miles (10.46 km2) (or 93.63%) is land and 0.275 square miles (0.71 km2) (or 6.37%) is water.
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 1,728.5 people per square mile (667.6/km²). There were 1,662 housing units at an average density of 525.8 per square mile (203.1/km²). 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.