Today, the Columbia River marks the boundary between Oregon and Washington. The river was named for the ship Columbia Rediviva whose captain, John Gray, sailed into the area in 1792. Gray was the first of many Euroamerican fur traders who would invade the area over the next half century.
The Maryhill Museum located near Goldendale, Washington, has a display of Plateau flat bags. The Plateau Culture Area is the area between the Cascade Mountains and the Rocky Mountains in Washington, Oregon, Idaho, British Columbia, and Western Montana. From north to south it runs from the Fraser River in the north to the Blue Mountains in the south. Much of the area is classified as semi-arid. Part of it is mountainous with pine forests in the higher elevations.
Long before the European invasion of North America, a number of autonomous, independent, and linguistically related peoples lived in contiguous territories in what would become the state of Washington. These peoples included the Yakama, Kittitas, Klikitat (also spelled Klickitat), Tainapam, and Wanapam. In 1855, the United States government forced a treaty on these people, grouping them together on what would become the Yakama Reservation and later forming the Consolidated Tribes and Bands of the Yakama Nation.
California Indian baskets are often considered the best in North America, and Pomo baskets are generally considered to be the best of the California baskets. In his book Encyclopedia of Native American Tribes, Carl Waldman reports:
“The Pomos created their beautiful baskets for functional purposes, but collectors now value them as works of fine art. In some Pomo baskets, the weaving is so tight that a microscope is needed to count the stitches.”