The Bannocks were allowed to retain some of their lands in a treaty, but over time, more settlers arrived and disregarded the terms of the treaty. As a result, the Bannocks were constrained to the Fort Hall Reservation where they faced food scarcity. After American ranchers had let their cattle graze in the Camas Prairie, the Bannocks declared war on the people they viewed as invaders on land that was their according to treaty.
On May 30, 1878, Chief Buffalo Horn and 200 warriors raided a group of settlers and took food and other resources. The chief led a second attack on June 8th at South Mountain, Idaho where he and his warriors faced 26 local militia. Chief Buffalo was wounded in this skirmish, but the war party decided to keep fighting through Idaho and neighboring states. Area settlers began to form militias for protection against the raiders and several skirmishes resulted in the deaths of settlers, American soldiers, and Bannocks warriors.
As US troops arrived in the region, the Bannock's were unable to secure more men and supplies to match the growing force against them. With their warriors exhausted and facing dwindling supplies, several tribal factions broke off and left the area in hopes of finding a new land where they might retain their traditional life. Others abandoned the fight and returned to the Fort Hall Reservation. In response to these skirmishes, the federal officials created stricter laws that severely limited the opportunity to leave the reservation.