Washington County, Illinois

Washington County
Location within the U.S. state of Illinois
Illinois's location within the U.S.
Coordinates: 38°21′N 89°25′W / 38.35°N 89.42°W / 38.35; -89.42
Country United States
State Illinois
FoundedJanuary 2, 1818
Named afterGeorge Washington
SeatNashville
Largest cityNashville
Area
  Total
564 sq mi (1,460 km2)
  Land563 sq mi (1,460 km2)
  Water1.3 sq mi (3 km2)  0.2%
Population
 (2020)
  Total
13,761
  Estimate 
(2023)
13,536
  Density24/sq mi (9.4/km2)
Time zoneUTC−6 (Central)
  Summer (DST)UTC−5 (CDT)
Congressional district12th
Websitewww.washingtonco.illinois.gov

Washington County is a county located in the U.S. state of Illinois. As of the 2020 census, it had a population of 13,761. Its county seat is Nashville. It is located in the southern portion of Illinois known locally as "Little Egypt".