Stanley County

Also known as Stanley County, South Dakota, Stanley County, SD

county in South Dakota, United States

Key facts

Country: United States
State: South Dakota
Founded: 1873 (created), 1890 (organized)
Named after: David S. Stanley
Seat: Fort Pierre
Largest city: Fort Pierre
Total: 1,517 sq mi (3,930 km )
Land: 1,444 sq mi (3,740 km )
Water: 73 sq mi (190 km ) 4.8%
Estimate 2025: 3,018
Density: 2.06/sq mi (0.797/km )
Western portion: UTC−7 ( Mountain )
Summer dst

Article

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.