The treaty council held at Waiilatpu (Place of the Rye Grass) in the Walla Walla Valley in May and June of 1855 forever changed the lives of Native Americans living in north-central and eastern Oregon. The fate of the Cayuse, Umatilla, and Walla Walla Indians who lived in that part of Oregon became closely tied to that of the Nez Perce, Palouse, and Yakama, who also participated in the treaty council. None of the tribes requested the council or wanted to surrender their lands, but representatives of the United States government championed the grand council and representatives of the tribes attended to protect their people and tribal interests.

By 1855, Oregon Indians had some knowledge of American policies, which included written treaties, conscribed boundaries, and surrender of traditional Indian lands. The Cayuse, Umatilla, and Walla Walla people attended the Walla Walla Council to listen, learn, and voice their position about the sacredness of the earth that held the bones of their ancestors. They attended to protect their secular and sacred interest, not to surrender their homelands, sovereignty, or way of life.

By 1855, the government of the United States had a great deal of experience dealing with American Indians. Over the years, the government had developed an Indian policy based on the nation's experiences with wars, treaties, boundaries, and trade. The United States continually negotiated with tribes in the best interest of the government, claiming millions of acres of Native land. When the terms of one agreement no longer suited the government, agents renegotiated the treaties to open more lands.

By the time of the Walla Walla Council, government agents had divided the tribes in the East, destroyed Native economies, forcefully removed thousands of Indian people to the trans-Mississippi West, created an Indian Territory, and opened millions of acres of Native traditional lands to non-Natives. 

Oregon Superintendent of Indian Affairs Joel Palmer and Washington Territorial Governor Isaac Stevens met with tribes during the Walla Walla Council to negotiate treaties and open Indian lands to white settlement. When Palmer and Stevens met with the Walla Walla, Cayuse, and Umatilla, tribal leaders first proposed that there would be no separate reservation for their people. They based their arguments on Indian law, or Tamanwit, which establishes the sacred relationship between humans and elements of the environment. Tamanwit also creates the proper relationships among humans and formed the foundation of Indian arguments made at the council.

She-Ca-Yah, or Five Crows, of the Cayuse explained to Palmer and Stevens that the "father in heaven" had "made all the earth" and at the time of creation "made us of the earth on this earth." Cayuse Chief Stikus explained that he did not "own" the earth, mountains, or rivers because these were gifts of creation to his people. Chief Stikus asked the Americans to think of the land as if it was their mother: "If your mothers were here in this country who gave you birth, suckled you and while you were sucking some person came and took your mother and left you alone and sold your mother, how would you feel then?" He explained that the earth was the mother of his people, the mother that gave and sustained life.

The Cayuse, Umatilla, and Walla Walla people lived off the bounty of the earth. For generations they had gathered nutritious roots, nuts, and seeds. They had fished and hunted, basing their economies on seasonal rounds through the mountains, valleys, and plateaus of the inland Northwest. Cayuse Chief Tauitau, or Young Chief, wondered what the earth would say to the Americans. He explained that the Creator had made all the plants and animals from which his people lived and given them their names. The Creator would not want the people to surrender the lands.

Palmer and Stevens avoided addressing the Indians' position and pushed their agenda of concluding three treaties and establishing reserves for the Umatilla, Yakama, and Nez Perce people. Palmer warned that white settlers would "steal your horses and cattle" if the Indians did not agree to boundaries. In their camps, the Indian leadership met to discuss the treaty, and they reluctantly decided to make an agreement with Stevens and Palmer.

In 1855, the sovereign nations of the Walla Walla, Umatilla, and Cayuse secured a reservation of 510,000 acres in northeastern Oregon. Through the Walla Walla, Cayuse, and Umatilla Treaty of June 9, 1855, the tribes lost 6.4 million acres of land and billions of dollars in resources. When government surveyors marked the land, they included only 245,000 acres within the reservation boundaries, a source of future land issues. The tribes reserved their right to hunt, fish, and gather at all usual and accustomed areas on and off the reservation, just as Stevens had promised in his oral presentation and recorded in the treaty proceedings.

The Walla Walla Council was a watershed in Oregon's history, and it triggered a major war between many Oregon and Washington tribes and the government. Over time, the Umatilla reservation became the homeland of several families from diverse tribes. The Walla Walla Council and the treaty that created the reservation have significant implications today for the Confederated Tribes of the Umatilla Indian Reservation, guaranteeing the tribe's legal status and its government-to-government relationship with the United States.