Together with the Hunkpapa and Sihasapa bands, the Standing Rock Sioux Tribe is part of what was known as the Great Sioux Nation. The peoples were highly decentralized. In 1868 the lands of the Great Sioux Nation were reduced in the Fort Laramie Treaty to the east side of the Missouri River and the state line of South Dakota in the west. The Black Hills, considered by the Sioux to be sacred land, are located in the center of territory awarded to the tribe.
