Jefferson County, Illinois

Jefferson County
Jefferson County Courthouse in Mount Vernon
Location within the U.S. state of Illinois
Illinois's location within the U.S.
Coordinates: 38°18′N 88°55′W / 38.3°N 88.92°W / 38.3; -88.92
Country United States
State Illinois
Founded1819
Named forThomas Jefferson
SeatMount Vernon
Largest cityMount Vernon
Area
 • Total584 sq mi (1,510 km2)
 • Land571 sq mi (1,480 km2)
 • Water13 sq mi (30 km2)  2.2%
Population
 • Total37,113
 • Density64/sq mi (25/km2)
Time zoneUTC−6 (Central)
 • Summer (DST)UTC−5 (CDT)
Websitewww.jeffersoncountyillinois.com

Jefferson County is a county located in the southern part of the U.S. state of Illinois. In the 2020 census, the population was 37,113.[1] The county seat is Mount Vernon.[2]

References

  1. 1.0 1.1 "QuickFacts: Jefferson County, Illinois". United States Census Bureau. Retrieved August 14, 2023.
  2. "Find a County". National Association of Counties. Archived from the original on May 31, 2011. Retrieved June 7, 2011.