South Dakota is located in the Midwestern region of the United States. Named after the Lakota and Dakota Sioux Native American tribes, South Dakota is the 5th least densely populated of the 50 United States. Pierre is the state capital, but Sioux Falls, with a population of approximately 165,000, is South Dakota's largest city.
South Dakota is bisected by the Missouri River, dividing South Dakota into two geographically and socially distinct halves known as 'East River' and 'West River.' A third region, called the Black Hills, rests near the eastern border of the state. Eastern South Dakota is where most of the state's population lives. Farming is popular here due to the fertile soil in the area. In the West River region, ranching is more predominant. The Great Plains cover most of the western two-thirds of this area. This region is dry and rugged. The landscape consists of plains, but it also has deep ravines, buttes and rolling hills. Tourism and defense spending also boost the economy. The Sioux tribe considers the Black Hills, a group of low mountains, sacred. These mountains are located in the southwest part of the state near Mount Rushmore, a major tourist destination for the state.