Stanley County, South Dakota
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. Geography Stanley County's northwestern boundary is defined by the Cheyenne River which flows eastward, to discharge into the Missouri River at the most northerly point of Stanley County. From there, the county's northeast boundary is defined by the southeastward-flowing Missouri. The county terrain consists of semi-arid rolling hills, carved by drainages. The area is partially devoted to agriculture. The terrain slopes to the east; its highest point is in the SW county corner, at ASL. The county has a total area of , of which is land and (4.8%) is water. The eastern portion of South Dakota's counties (48 of 66) observe Central Time; the western counties (18 of 66) observe Mountain Time. Stanley County is on the western end of counties which observe Central Time, and its residents are split east–west in their time observance. Although Fort Pierre, the seat of Stanley County, is located in the Mountain Time Zone, most residents of the city use Central Time because of close social and economic ties with Pierre, which is located in the Central Time Zone. Major highways U.S. Highway 14 U.S. Highway 83 South Dakota Highway 34 South Dakota Highway 63 South Dakota Highway 1806 Adjacent counties Dewey County - north Sully County - northeast Hughes County - east Lyman County - southeast Jones County - south Haakon County - west Ziebach County - northwest Protected areas Antelope Creek State Game Production Area Antelope Creek State Lakeside Use Area Brush Creek State Game Production Area Chantier Creek State Game Production Area Chantier Creek State Lakeside Use Area Fort George State Game Production Area Fort Pierre National Grassland (part) Foster Bay State Lakeside Use Area Frozen Man Creek State Game Production Area Hayes Lake State Game Production Area Minneconjou State Game Production Area Minneconjou State Lakeside Use Area Oahe Downstream State Recreation Area Schomer Draw State Game Production Area West Shore State Lakeside Use Area Lakes Lake Oahe (part) Lake Sharpe (part) Demographics 2020 census As of the census of 2020, there were 2,980 people. 2010 census As of the census of 2010, there were 2,966 people, 1,228 households, and 857 families in the county. The population density was . There were 1,387 housing units at an average density of . The racial makeup of the county was 90.0% white, 6.6% American Indian, 0.3% black or African American, 0.1% Asian, 0.2% from other races, and 2.8% from two or more races. Those of Hispanic or Latino origin made up 0.7% of the population. In terms of ancestry, 46.4% were German, 12.5% were Irish, 10.8% were English, 10.7% were Norwegian, 8.4% were