Hughes County, South Dakota Hughes County, South Dakota Hughes County is a county located in the U.S. state of South Dakota. As of the 2010 census, the population was 17,022, making it the least populous capital county in the nation, and the twelfth-most populous county in South Dakota. Its county seat is Pierre, the state capital. The county was created in 1873 and organized in 1880. It was named for Alexander Hughes, a legislator. Hughes County is part of the Pierre, SD Micropolitan Statistical Area. According to the U.S. Census Bureau, the county has a total area of , of which is land and
South Dakota Highway 89 South Dakota Highway 89 South Dakota Highway 89 (SD 89) is a state highway in the southwestern part of the U.S. state of South Dakota. The highway travels from U.S. Route 18 (US 18) near Minnekahta to SD 87 in Custer State Park. SD 89 is concurrent with US 385 from Pringle to Custer. The portion of the highway from Custer to SD 87 is part of the Peter Norbeck Scenic Byway. SD 89 was established in 1950 from Spearfish to Minnekahta. The section from SD 87 to Spearfish was redesignated as US 14 Alternate and U.S. Forest Service roads.