Yuma Crossing
Immediately after the Mexican–American War in 1848, the U.S. Army built Fort Yuma here to protect travelers from Indians raiding the area. It was the center point of conflict in the Yuma War of 1850–53. From 1864–1890, the fort and nearby facilities was the main army base to support the US Army's efforts to control the Indians throughout the greater southwest.
Cayuse War
The Cayuse War was an armed conflict that took place in the Northwestern United States from 1847 to 1855 between the Cayuse people of the region and the United States Government and local American settlers. Caused in part by the influx of disease and settlers to the region, the immediate start of the conflict occurred in 1847 when the Whitman Massacre took place at the Whitman Mission near present day Walla Walla, Washington when fourteen people were killed in and around the mission. Over the next few years the Provisional Government of Oregon and later the United States Army battled the Indians east of the Cascades. This was the first of several wars between the Indians and American settlers in that region that would lead to the negotiations between the United States and Indians of the Columbia Plateau, creating a number of Indian reservations.