South Dakota is a Midwestern state in the United States. It is named after the Lakota and Dakota (Sioux) American Indian tribes. South Dakota was admitted to the Union on November 2, 1889. North Dakota was admitted on the same day. It is probably best known as the location of Mount Rushmore. Human beings have lived in what is today South Dakota for at least several thousand years. French and other European explorers in the 1700s encountered a variety of groups including the Omaha and Arikara (Ree), but by the early 1800s the Sioux (Dakota, Lakota, and Nakota) were dominant. In 1743, the LaVerendrye brothers buried a plate near the modern capital Pierre (pronounced as "peer") claiming the region for France as part of greater Louisiana. In 1803, the United States purchased the Louisiana Territory from Napoleon, though the native peoples inhabiting most of this area were not aware of the transaction.
South Dakota is bordered to the north by North Dakota; to the south by Nebraska; to the east by Iowa and Minnesota; and to the west by Wyoming and Montana. It is one of the six states of the Frontier Strip. The Missouri River runs through the central part of South Dakota. To the east of the river lie low hills and lakes formed by glaciers. Fertile farm country covers the area. To the west of the river the land consists of deep canyons and rolling plains. South Dakota is comprised of four major land regions: the Drift Prairie, the Dissected Till Plains, the Great Plains, and the Black Hills.