Yakama, North American Indian tribe that lived along the Columbia, Yakima, and Wenatchee rivers in what is now the south-central region of the U.S. state of Washington. As with many other Sahaptin-speaking Plateau Indians, the Yakama were primarily salmon fishers before colonization. In the early 21st century they continued to be involved in wildlife management and fisheries.
The Yakama acquired historical distinction in the Yakama Indian Wars (1855–58), an attempt by the tribe to resist U.S. forces intent upon clearing the Washington Territory for prospectors and settlers. The conflict stemmed from a treaty that had been negotiated in 1855, according to which the Yakama and 13 other tribes (identified in the treaty as Kah-milt-pah, Klikatat, Klinquit, Kow-was-say-ee, Li-ay-was, Oche-chotes, Palouse, Pisquose, Se-ap-cat, Shyiks, Skin-pah, Wenatshapam, and Wish-ham) were to be placed on a reservation and confederated as the Yakama Nation. Before the treaty could be ratified, however, a force united under the leadership of Yakama chief Kamaiakan, who declared his intention to drive all nonnatives from the region. After initial Yakama successes, the uprising spread to other tribes in Washington and Oregon. Three years of raids, ambushes, and engagements followed until September 1858, when the Native American forces were decisively defeated at the Battle of Four Lakes on a tributary of the Spokane River.
In 1859 the treaty of 1855 was effected, with the Yakama and most of the other tribes confined to reservations and their fertile ancestral lands opened to colonial appropriation. Since that time, all the residents of the Yakama Reservation have been considered members of the Yakama Nation. Several tribes in the region, notably the Palouse, refused to acknowledge the treaty and would not enter the reservation.
Early 21st-century population estimates indicated some 11,000 individuals of Yakama Nation ancestry.