South Dakota, a state in the north-central United States. It is roughly rectangular in shape and occupies more than 77,000 square miles (nearly 200,000 km 2)of the prairies and plains that lie between the Great Lakes and the Rockies. Along its borders are six states: North Dakota, Montana, Wyoming, Nebraska, Iowa, and Minnesota. Across its midsection flows the broad Missouri River, which divides the state into two parts, called East River and West River by South Dakotans. The geographical center of the United States is in Butte County, near the Montana and Wyoming borders.
Unlike many states, South Dakota is still a land of small towns and few cities, of large farms and ranches, and of wide-open spaces resembling those found by the early homesteaders. It is still the home of most of the Sioux Indians, whose exploits and battles under such chiefs as Crazy Horse, Sitting Bull, and Red Cloud are part of the history of the state.
South Dakota is also the land of the Black Hills, where Wild Bill Hickok, Calamity Jane, Deadwood Dick, and other legendary characters were part of a wild gold rush era that began in the 1870's. Some of the flavor of those days is preserved in the Black Hills, especially in the city of Deadwood. The Black Hills region, and probably the entire state, is best known, however, for Mount Rushmore, a national memorial featuring the granite-sculptured faces of Presidents Washington, Jefferson, Lincoln, and Theodore Roosevelt.South Dakota's state bird is the ring-necked pheasant.