South Dakota South Dakota South Dakota () is a U.S. state in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux Native American tribes, who compose a large portion of the population and historically dominated the territory. South Dakota is the seventeenth largest by area, but the fifth smallest by population and the 5th least densely populated of the 50 United States. As the southern part of the former Dakota Territory, South Dakota became a state on November 2, 1889, simultaneously with North Dakota. Pierre is the state capital and Sioux Falls, with a population
South Dakota Highway 123 South Dakota Highway 123 South Dakota Highway 123 (SD 123) is a state highway in the U.S. state of South Dakota that runs from U.S. Route 12 (US 12) near Marvin to SD 15 in Wilmot. It is maintained by the South Dakota Department of Transportation (SDDOT), and is not part of the National Highway System. SD 123 begins at an intersection with US 12 east of Marvin in Grant County and begins north through open plains. The highway enters Roberts County north of its southern terminus and continues north through rolling farmland. North of the county line, the route