Perry County is in Illinois. According to the 2020 census, it had a population of 20,945. Its county seat is Pinckneyville. It is located in the southern portion of Illinois known as "Little Egypt".

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.