Geography of South Dakota of the federal or state government, such as Badlands National Park, Wind Cave National Park, and Custer State Park, are located in the state. In 2011, the population of South Dakota was estimated to be 824,082, and the state ranks fifth-lowest in both total population as well as population density in the United States. Sioux Falls, with a population of just over 170,000, is the largest city in the state. Rapid City ranks as South Dakota's second-largest city, and Pierre is the state capital. Historically a very agricultural state, the service and tourism sectors have grown in economic importance in
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