Franklin County, Illinois

Franklin County, Illinois
Location within the U.S. state of Illinois
Coordinates: 37°59′N 88°55′W / 37.99°N 88.92°W / 37.99; -88.92
Country United States
State Illinois
FoundedJanuary 2, 1818
Named afterBenjamin Franklin
SeatBenton
Largest cityWest Frankfort
Area
 • Total
432 sq mi (1,120 km2)
 • Land409 sq mi (1,060 km2)
 • Water23 sq mi (60 km2)  5.2%
Population
 (2020)
 • Total
37,804
 • Estimate 
(2024)
37,033
 • Density92.4/sq mi (35.7/km2)
Time zoneUTC−6 (Central)
 • Summer (DST)UTC−5 (CDT)
Congressional district12th
Websitewww.franklincountyil.gov

Franklin County is a county in Southern Illinois. At the 2020 census, it had a population of 37,804. The largest city is West Frankfort and the county seat is Benton. Franklin County is located in the Metro Lakeland area of Southern Illinois.