Sebastian County, Arkansas

Sebastian County
Location within the U.S. state of Arkansas
Arkansas's location within the U.S.
Coordinates: 35°35′39″N 94°15′29″W / 35.5942°N 94.2581°W / 35.5942; -94.2581
Country United States
State Arkansas
FoundedJanuary 6, 1851
Named afterWilliam K. Sebastian
SeatFort Smith (northern district);
Greenwood (southern district)
Largest cityFort Smith
Area
  Total
546 sq mi (1,410 km2)
  Land532 sq mi (1,380 km2)
  Water14 sq mi (40 km2)  2.6%
Population
 (2020)
  Total
127,799
  Estimate 
(2023)
129,098
  Density230/sq mi (90/km2)
Time zoneUTC−6 (Central)
  Summer (DST)UTC−5 (CDT)
Congressional districts3rd, 4th
Websitewww.sebastiancountyar.gov

Sebastian County is a county located in the U.S. state of Arkansas. As of the 2020 census, the population was 127,799, making it the fourth-most populous county in Arkansas. The county has two county seats, Greenwood and Fort Smith.

Sebastian County is part of the Fort Smith, AR-OK Metropolitan Statistical Area.