Following the Custer fight at Little Big Horn, the Northern Cheyenne were sent to Oklahoma, then known as Indian Territory. The Cheyenne were not accustomed to the hot conditions of Oklahoma and they began dying in great numbers. In desperation, a small band left the reservation and headed north, settling in the Tongue River watershed in Montana Territory. Here, they established homesteads in the northern edge of the Big Horn River Basin, which they considered their natural home. And, because their settlement was peaceful, President Arthur, by executive order, established the Tongue River Reservation, making it legal for them to stay there.