Cayuse Indians. A Waiilatpuan tribe formerly occupying the territory about the heads of Walla Walla, Umatilla, and Grande Ronde Rivers and from the Blue mountains to Deschutes River in Washington and Oregon. The tribe has always been closely associated with the neighboring Nez Percé and Walla Walla, and was regarded by the early explorers and writers as belonging to the same stock. So far as the available evidence goes, however, they must be considered linguistically independent. The Cayuse have always been noted for their bravery, and owing largely to their constant struggles with the Snake and other tribes, have been numerically weak. According to Gibbs there were few pure-blood Cayuse left in 1851, intermarriage, particularly with the Nez Percé, having been so prevalent that even the language was falling into disuse. In 1855 the Cayuse joined in the treaty by which the Umatilla Reservation was formed, and since that time have resided within its limits. Their number is officially reported as 404 in 1904; but this figure is misleading, as careful inquiry in 1902 failed to discover a single one of pure blood on the reservation and the language is practically extinct. The tribe acquired wide notoriety in the early days of the white settlement of the territory. In 1838 a mission was established among the Cayuse by Marcus Whitman at the site of the present town of Whitman, Walla Walla County, Washington. in 1847 smallpox carried off a large part of the tribe. The Cayuse, believing the missionaries to be the cause, attacked them, murdered Whitman and a number of others. and destroyed the mission. Owing to the confusion in the early accounts it is difficult to differentiate the Cayuse from the Nez Percé and Walla Walla, but there is no reason to suppose that in habits and customs they differed markedly from those tribes.