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 36 in 1926. At that time, it continued further west to the Wyoming border, utilizing the current route of US 16A to Custer, and U.S. Route 16 west of Custer; US 16 went northwest from Rapid City. The western terminus was pulled back to its present location around 1935, when US 16 was rerouted southwest through the Black Hills. In 1933 and 1934, this route was also part of U.S. Route 216, which then continued north to Rapid City. South Dakota Highway 36 South Dakota Highway 36 (SD 36) is an east–west state route located in southwest South Dakota. It begins