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