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 10 a curve to the south and then to the southeast, it reaches its eastern terminus at the Minnesota state line. Here, the roadway continues as Minnesota State Highway 28 (MN 28). SD 10 was formerly the "Glacier Trail". It was also formerly known as SD 12. The highway was redesignated in 1927, presumably to avoid confusion with nearby US 12. The segment of the highway west of US 83 was added in the early 1960s. South Dakota Highway 10 South Dakota Highway 10 (SD 10) is a state highway in the north-central and northeastern portions of the U.S. state of