The Treaty of Fort Laramie failed due to the discovery of gold in the Black Hills. Although the treaty was meant to recognize the Black Hills as part of the Sioux Indian's reservation, the U.S. military backed expeditions by miners into the area in search of gold.
Following years of battles and skirmishes in the Dakota territory, a conference was held in 1868 at Fort Laramie, in present day Wyoming, between the U.S. government and the leadership of the Sioux Indian tribe. The treaty, which set up a reservation for the indigenous Sioux, formed a short-lived peace between the American settlers in the Dakota Territory and the members of the tribe. Due to the location of the reservation, the agreement gave the Sioux exclusive rights to the Black Hills, which were sacred lands to the tribe.
In 1874, General George Custer and his forces gave military protection on gold mining expeditions into the Black Hills. Miners soon found gold, and the white settlers, with the backing of the U.S. government, were soon breaking the treaty formed just six years earlier. In 1876, Custer's forces were defeated at Little Big Horn River by Sioux and Cheyenne Indians. In the aftermath of the defeat, the U.S. government officially took the Black Hills lands away from the Sioux in 1877.