On June 25th, 1876, Native American forces led by Chiefs Crazy Horse and Sitting Bull defeated the U.S. Army troops of Lieutenant Colonel George Armstrong Custer in a bloody battle near southern Montana’s Little Bighorn River. The Battle of Little Bighorn–also called Custer’s Last Stand  –marked the most decisive Native American victory and the worst U.S. Army defeat in the long Plains Indian War. While complicated, the generally accepted reason for the battle is that the discovery of gold in South Dakota’s Black Hills in 1875 led to the U.S. government disregarding previous treaty agreements. The gruesome fate of Custer and his men outraged many white Americans and confirmed their image of the Indians as wild and bloodthirsty. Meanwhile, the U.S. government increased its efforts to subdue the tribes. Within five years, almost all of the Sioux and Cheyenne would be confined to reservations.