Greene County, Illinois

Greene County
County
Greene County Courthouse
Location within the U.S. state of Illinois
Illinois's location within the U.S.
Coordinates: 39°21′N 90°23′W / 39.35°N 90.39°W / 39.35; -90.39
Country	United States
State	Illinois
Founded	1821
Named for	Nathanael Greene
Seat	Carrollton
Largest city	Carrollton
Area
• Total	546 sq mi (1,410 km2)
• Land	543 sq mi (1,410 km2)
• Water	3.3 sq mi (9 km2)  0.6%
Population  (2020)
• Total	11,843
• Density	22/sq mi (8.4/km2)
Time zone	UTC−6 (Central)
• Summer (DST)	UTC−5 (CDT)
Congressional district	15th
Website	https://

Greene County is a county located in the U.S. state of Illinois. According to the 2020 United States Census, it has a population of 11,843.^[1] Its county seat is Carrollton.^[2]

A notable archaeological area, the Koster Site, has produced evidence of more than 7,000 years of human habitation. Artifacts from the site are displayed at the Center for American Archeology in Kampsville, Illinois.