Located primarily in South Dakota, the Sioux tribal reservations are: Rosebud, Cheyenne River, Pine Ridge, Standing Rock, Lower Brule, Crow Creek, Lake Traverse, Yankton, and Flandreau.

When reservations were introduced in the mid-1800s, the plots of land represented an alternative to starvation and constant attack of native tribes by the U.S. Army. Today, many Sioux regard reservations as a key to the survival of their culture and traditional way of life, as one of the only remaining links to the past.

In the 19th century, the Sioux roamed freely across the Great Plains of the North American west, an area representing more than one million square miles. It was common for tribes to fight amongst each other to expand territory, and to increase power and populations. However, in the face of growing numbers of American settlers on the Plains, tribes began forming alliances to protect their land and ways of life. The U.S. government felt increasing pressure to take action so enacted a policy to create restricted colonies for native peoples through a set of treaties. These legal documents established territorial boundaries and recognized the rights of the Plains Indians as a sovereign nation.

The tribes of the Great Sioux Nation signed treaties with the United States government in 1824, 1851, 1863, and 1868. Under the terms of the Fort Laramie Treaty of 1868 the
Sioux were restricted to one
large reservation, the Great Sioux Reservation, which encompassed large parts of South Dakota, North Dakota, Wyoming, Montana, and Nebraska. In spite of the treaty, American settlers flooded onto Sioux land, causing tension between the two groups. The government's desire to expand the railroad and the discovery of gold in the Black Hills escalated fighting between Plains Indians and government soldiers. The railroad was threatening buffalo herds, the key source of food for the Sioux, and the gold rush led thousands of miners into sacred Sioux territory. In 1875, the Sioux refused to alter the terms of the treaty to suit the Americans. Sitting Bull put it in no uncertain terms: the Black Hills were not for sale.

The United States tore up the Fort Laramie treaty and sent the Army to seize the Black Hills by force. In 1876, the government issued an order that all Sioux bands move onto reservations during the winter of that year. The decade that followed was a deadly one for the Sioux, as they fought battles against the U.S. Army, fending off starvation and disease. In 1889, the Lakota agreed to relinquish about 10 million acres, with the remainder being divided into five reservations under jurisdiction of five corresponding agencies: Cheyenne River, Rosebud, Pine Ridge, Lower Brule and Standing Rock.

The federal government distributed food rations and clothing on the reservations. In exchange, the government asked native people to adopt a new way of life. Almost overnight, warriors were transformed into farmers and stock raisers. Children, once educated by grandparents, aunts, and uncles, attended schools where they learned to read and write in English, abandoning their native tongue. Reservation policies restricted the movement, autonomy, and religious freedom of the Sioux. In 1883, the government introduced its Code of Religious Offences, outlawing the Sun Dance and other spiritual practices. Missionaries came to the reservations, converting many to Christianity.

By 1896, the federal government had completed allotment agreements with members of the Plains tribes, and opened the rest of the land to non-native settlements. They also reduced tribal lands to a fraction of the size of original reservations.

In 1946, Congress created the Indian Claims Commission, an agency designed to deal with outstanding legal claims regarding treaties, most involving land disputes. In 1980, the U.S. Supreme Court awarded the Sioux $105. million for native land in South Dakota the government had taken illegally in 1877. The Lakota refused to accept the money because they wanted the land back. The Lakota still refuse to accept the money; the federal government holds it in trust for them.