Stanley County, South Dakota

Stanley County
Watercolor drawing of Fort Pierre Chouteau. Dated 1854.
Location within the U.S. state of South Dakota
South Dakota's location within the U.S.
Coordinates: 44°24′N 100°45′W / 44.4°N 100.75°W / 44.4; -100.75
Country United States
State South Dakota
Founded1873 (created)
1890 (organized)
Named afterDavid S. Stanley
SeatFort Pierre
Largest cityFort Pierre
Area
  Total
1,517 sq mi (3,930 km2)
  Land1,444 sq mi (3,740 km2)
  Water73 sq mi (190 km2)  4.8%
Population
 (2020)
  Total
2,980
  Estimate 
(2024)
3,015
  Density2.0/sq mi (0.76/km2)
Time zones
western portionUTC−7 (Mountain)
  Summer (DST)UTC−6 (MDT)
eastern portionUTC−6 (Central)
  Summer (DST)UTC−5 (CDT)
Congressional districtAt-large
Websitewww.stanleycounty.org

Stanley County is a county in the U.S. state of South Dakota. As of the 2020 census, the population was 2,980. Its county seat is Fort Pierre. The county was created in 1873, and was organized in 1890. It is named for David S. Stanley, a commander at Fort Sully from 1866 to 1874, which was located nearby.

Stanley County is included in the Pierre, SD Micropolitan Statistical Area.