Tags: Ethnic Group.
The Confederated Tribes of the Umatilla Indian Reservation is a federally recognized confederation of three Sahaptin-speaking Native American tribes who traditionally inhabited the Columbia River Plateau region: the Cayuse Umatilla and Walla Walla.When the leaders of the Walla Walla Cayuse and Umatilla peoples signed the Treaty of Walla Walla with the United States in 1855 they ceded 6.4 million acres of homeland in what is now northeastern Oregon and southeastern Washington in exchange for a reservation and the promise of annuities in the form of goods and supplies.The tribes share the Reservation which has 271.047 sq mi (702.009 km²) in Umatilla County in central Oregon state.
