The Cayuse called themselves the Liksiyu in the Cayuse language. Originally located in present-day northeastern Oregon and southeastern Washington, they lived adjacent to territory occupied by the Nez Perce and had close associations with them. Like the Plains tribes, the Cayuse placed a high premium on warfare and were skilled horsemen. They developed the Cayuse pony. The Cayuse ceded most of their traditional territory to the United States in 1855 by treaty and moved to the Umatilla Reservation, where they have formed a confederated tribe.