Sitting Bull as hostiles those Sioux and others living off the reservation, Native Americans gathered at Sitting Bull's camp. He took an active role in encouraging this "unity camp". He sent scouts to the reservations to recruit warriors, and told the Hunkpapa to share supplies with those Native Americans who joined them. An example of his generosity was Sitting Bull's taking care of Wooden Leg's Northern Cheyenne tribe. They had been impoverished by Captain Reynold's March 17, 1876 attack and fled to Sitting Bull's camp for safety. Over the course of the first half of 1876, Sitting Bull's camp continually expanded, as
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.