The Standing Rock Indian Reservation is located in North Dakota and South Dakota in the United States, and is occupied by ethnic Hunkpapa Lakota, Sihasapa Lakota and Yanktonai Dakota. The sixth-largest Native American reservation in land area in the US, Standing Rock includes all of Sioux County, North Dakota, and all of Corson County, South Dakota, plus slivers of northern Dewey and Ziebach counties in South Dakota, along their northern county lines at Highway 20. The reservation has a land area of 9,251.2 square kilometers (3,571.9 sq mi) and a population of 8,217 as of the 2010 census. The largest communities on the reservation are Fort Yates, Cannon Ball and McLaughlin.

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.

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