Buffalo County

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

county in South Dakota, United States

Key facts

Country: United States
State: South Dakota
Founded: 1864 (created), 1871 (organized)
Named after: American buffalo
Seat: Gann Valley
Largest community: Fort Thompson
Total: 488 sq mi (1,260 km )
Land: 471 sq mi (1,220 km )
Water: 16 sq mi (41 km ) 3.4%
Estimate 2025: 1,802
Density: 4.14/sq mi (1.60/km )
Time zone: UTC−6 ( Central )
Summer dst

Article

Buffalo County is a county in the U.S. state of South Dakota. As of the 2020 census, the population was 1,948. Its county seat is Gann Valley which, at 10 people, is the least populous county seat in the United States. The county was created in 1864, and was organized in 1871 as part of the Dakota Territory.

In 2010, the center of population of South Dakota was located in eastern Buffalo County. The Crow Creek Indian Reservation, inhabited by the Crow Creek Sioux Tribe, makes up the majority of Buffalo County.