In the mid-19th Century the Yakama Indians lived along the Columbia and Yakima Rivers on the plateau north of the Columbia, on the inland side of the Cascade Range. In addition to long-standing relations with neighbouring tribes, they also had a long-established trade relationship with the Hudson’s Bay Company (HBC), based out of Forts Vancouver, Walla Walla and Okanagan dating back to the first trade with whites via the traders of the North West Company (which was later absorbed into the HBC). The Cayuse and Yakama and other peoples of the region, all former clients of the HBC and friendly with the “King George” (British) and “Pasiooks (French Canadian/Metis) traders of the Hudson’s Bay, found themselves facing different attitudes and policies for dealing with aboriginal peoples, and the pressure of an impeding flood of settlement led to conflicts throughout the former Oregon Country.
In May and June 1855, Isaac Stevens, the first governor of the newly formed Washington Territory, and Joel Palmer, Superintendent of the Oregon Territory, enacted three treaties at the Walla Walla Council (1855). The Walla Walla, the Umatilla and the Cayuse tribes were coerced to move from 4 million acres (1.6 million hectares) of tribal lands to a reservation in northeastern Oregon. Over time, this was reduced down to 95,000 acres (38,460 ha). In a second treaty, fourteen different tribal groups agreed to go onto the Yakama Indian Reservation, giving up a combined 29,000 square miles of land. Under the third treaty, the Nez Perce were confined to a reservation that included parts of southeastern Washington, northeastern Oregon, and west-central Idaho.
The same year gold was discovered on the recently established Yakama reservation, and conflict erupted between encroaching white miners and tribes of the Plateau. The tribes eventually united together under the leadership of Yakama chief Kamiakin, marking the start of the Yakima War.
The U.S. Army sent troops to the region, and in August 1856, Robert S. Garnett supervised the construction of Fort Simcoe as a military post. Initially the conflict was limited to the Yakama, but eventually the Walla Walla and Cayuse were drawn into the war, following the lead of the Yakama, and a number of raids and battles took place. Perhaps the best known of these raids culminated in the Battle of Seattle in which an unknown number of raiders briefly crossed the Cascade Range to engage settlers, Marines and the U.S. Navy before retiring.
The last phase of the war, sometimes referred to as the Coeur d’Alene War or Palouse War came in 1858. General Newman S. Clarke commanded the Department of the Pacific and sent a force under Col. George Wright to deal with the recent fighting. At the Battle of Four Lakes, near Spokane, Washington, (September 1858), Wright inflicted a decisive defeat on the Indians. He then called a council of all the local Indians at Latah Creek (southwest of Spokane), and there on September 23 imposed a peace treaty, under which most of the tribes were to go to reservations.