Living east of the Cascades, the Indians of Oregon's interior had access to unparalleled riverine resources. The Columbia and its tributaries--Deschutes, John Day, Umatilla, Snake, Grande Ronde, and Owyhee--were filled with fish. For at least 10,000 years Celilo Falls, the place where the Columbia dropped over a series of basalt ledges and surged almost on its side through Five Mile Rapids, was their major fishery. So vast were the harvests of fish, the tribes that gathered at Celilo controlled one of the greatest, longest-operating trade centers in the American West. The commerce of Celilo was varied. Arriving from the coast were sleek dugout canoes, paddles, cattail matting, prized shells, and special foodstuffs such as smelt. From the south came war captives to be bartered into slavery, obsidian from more than twenty quarry sites destined for the hands of craftsmen in Washington and British Columbia (where none of this vital projectile material existed naturally), and, just prior to Euro-American contact, herds of horses. From the east came carefully preserved beargrass for basketry, buffalo hides and saddles and, again just before the arrival of American explorers, remarkable trade goods--glass beads, weapons, metal-tipped tools, and cotton and woolen cloth and clothing.
The Plateau people occupied a challenging environment. Summers were hot and windy; winters were cold and windy. The lodges to shelter human activities thus varied from pole-frame, mat-covered summer encampments to semisubterranean pit houses, framed with a cone of rafters covered with brush and earth to provide a refuge from the icy cold, snow, and darkness of winter. In spite of its harshness the region abounded in life. Following annual ceremonies, the women harvested the roots of wild celeries, balsams, and lomatiums. They picked huckleberries in the nearby mountains and gathered nutritious moss. The men ran down deer in the snow to secure not only meat but hides to tan for clothing and moccasins. They dipped, clubbed, netted, and speared salmon and wind-dried them in curing sheds along the river.
Oregon's Plateau Indians included the Wasco, Wishram, Warm Springs (or Tenino), John Day, Cayuse, Umatilla, and Nez Perce. They lived from the Cascade Mountains to the Wallowas, from the margins of the rivers to summer camps at high elevations. Their seasonal round responded to the rhythms of nature and took them from fishing camps to berry-picking sites and hunting camps high in the mountains. With the onset of winter they returned to lower elevations and their permanent villages along the margins of the principal streams.