Sullivan County, Indiana

39°05′N 87°25′W / 39.09°N 87.41°W / 39.09; -87.41

Sullivan County
Sullivan County Courthouse
Location within the U.S. state of Indiana
Indiana's location within the U.S.
Coordinates: 39°05′N 87°25′W / 39.09°N 87.41°W / 39.09; -87.41
Country United States
State Indiana
FoundedJanuary 15, 1817 (created)
February 1817 (organized)
Named afterGeneral Daniel Sullivan
SeatSullivan
Largest citySullivan
Area
  Total
454.12 sq mi (1,176.2 km2)
  Land447.14 sq mi (1,158.1 km2)
  Water6.97 sq mi (18.1 km2)  1.53%
Population
 (2020)
  Total
20,817
  Estimate 
(2023)
20,757
  Density46/sq mi (18/km2)
Time zoneUTC−5 (Eastern)
  Summer (DST)UTC−4 (EDT)
Congressional district8th
Websitewww.sullivancounty.in.gov
Indiana county number 77

Sullivan County is a county in the U.S. state of Indiana, and determined by the US Census Bureau to include the mean center of U.S. population in 1940. As of 2023, the population was estimated at 20,757. The county seat (and the county's only incorporated city) is Sullivan. Sullivan County is included in the Terre Haute metropolitan area.