[2] 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.

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.

Historian Verne Ray has identified seventy-six traditional Cayuse Village sites, most temporary, seasonal sites; five separate villages in the Walla Walla Valley and seven Cayuse Bands scattered throughout Eastern Oregon and Washington.

No longer restricted to what they could carry or what their dogs could pull, they moved into new areas, traveling as far east as the Great Plains and as far south as California, to hunt, trade, fight, and capture slaves.

Horses improved the range and effectiveness of war parties, making it possible for Cayuses to dominate their sedentary neighbors on the Columbia.

They claimed ownership of The Dalles, the great fishery and trade emporium of the Columbia, forcing the weaker bands in that area to pay them tribute in the form of salmon and other goods.

As white settlers moved into their territory in large numbers following the opening of the Oregon Trail in 1842, the Cayuse suffered.

In 1838, Marcus Whitman and his wife Narcissa established a mission among the Cayuse at Waiilatpu ("Place of the Rye Grass"), a site about seven miles from the present-day city of Walla Walla and about a quarter mile east of where the Cayuse Pásxa winter village was located.

In 1847, a measles epidemic, suspected by some to be contracted from white settlers, resulted in high fatalities among the tribe.

A small group of Cayuse, after putting Witmans medicine to the test with both sick and non sick individuals, and which all test individuals died, believed the missionaries were deliberately poisoning their native people, since a much higher percentage of the natives were dying from the measles than were the whites.

During the mid-twentieth century, some members moved to cities under the Indian Relocation Act of 1956, an effort to give better access for contemporary jobs.

They also used them for their trip over the Rocky Mountains each year to hunt a supply of buffalo to bring back for their families.

The men considered bravery to be an important quality, with brave warriors being held in high esteem.

Weyíiletpuu was a dialect of the Nez Perce language spoken by the Cayuse inhabitants of the Confederated Tribes of the Umatilla Indian Reservation.