Sitting Bull did not agree to the treaty. He told the Jesuit missionary, Pierre Jean De Smet, who sought him out on behalf of the government: "I wish all to know that I do not propose to sell any part of my country." He continued his hit-and-run attacks on forts in the upper Missouri area throughout the late 1860s and early 1870s. The events of 1866–1868 mark a historically debated period of Sitting Bull's life. According to historian Stanley Vestal, who conducted interviews with surviving Hunkpapa in 1930, Sitting Bull was made "Supreme Chief of the whole Sioux Nation" at this time.
Sitting Bull River (known as the Greasy Grass River to the Lakota) on June 25, 1876. The U.S. Army did not realize how large the camp was. More than 2,000 Native American warriors had left their reservations to follow Sitting Bull. Inspired by a vision of Sitting Bull's, in which he saw U.S. soldiers being killed as they entered the tribe's camp, the Cheyenne and Lakota fought back. Custer's badly outnumbered troops lost ground quickly and were forced to retreat. The tribes led a counter-attack against the soldiers on a nearby ridge, ultimately annihilating them. The Native Americans' victory celebrations were short-lived.