South Dakota (/- dəˈkoʊtə/ ⓘ; Sioux: Dakȟóta itókaga, pronounced [daˈkˣota iˈtokaga]) is a U.S. state in the North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Dakota Sioux Native American tribe, which comprises a large portion of the population with nine reservations currently in the state and has historically dominated the territory.[citation needed] South Dakota is the 17th largest by area, but the 5th least populous, 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. They are the 39th and 40th states admitted to the union; President Benjamin Harrison shuffled the statehood papers before signing them so that no one could tell which became a state first.Pierre is the state capital, and Sioux Falls, with a population of about 192,200, is South Dakota’s most populous city.

South Dakota is bordered by the states of North Dakota (to the north), Minnesota (to the east), Iowa (to the southeast), Nebraska (to the south), Wyoming (to the west), and Montana (to the northwest). The state is bisected by the Missouri River, dividing South Dakota into two geographically and socially distinct halves, known to residents as “East River” and “West River”.