Marion County, Illinois

Marion County
Marion County Courthouse in Salem
Flag of Marion County
Map of Illinois highlighting Marion County
Location within the U.S. state of Illinois
Map of the United States highlighting Illinois
Illinois's location within the U.S.
Coordinates: 38°39′N 88°55′W / 38.65°N 88.92°W / 38.65; -88.92
Country United States
State Illinois
Founded1823
Named forFrancis Marion
SeatSalem
Largest cityCentralia
Area
 • Total576 sq mi (1,490 km2)
 • Land572 sq mi (1,480 km2)
 • Water3.7 sq mi (10 km2)  0.6%
Population
 (2020)
 • Total37,729
 • Estimate 
(2023)
36,673 Decrease
 • Density66/sq mi (25/km2)
Time zoneUTC−6 (Central)
 • Summer (DST)UTC−5 (CDT)
Congressional district15th

Marion County is a county located in the U.S. state of Illinois. According to the 2020 census, it had a population of 37,729.[1] Its county seat is Salem.[2] Marion County comprises the Centralia, IL Micropolitan Statistical Area, which is included in the St. Louis-St. Charles-Farmington, MO-IL Combined Statistical Area.

  1. ^ "Marion County, Illinois". United States Census Bureau. Retrieved June 10, 2023.
  2. ^ "Find a County". National Association of Counties. Archived from the original on May 31, 2011. Retrieved June 7, 2011.