The Klikitats may have originated south of the Columbia River, moving north in the prehistoric period to become skilled horsepeople and fighters after they acquired horses around 1700. The 1805 encounter with Meriwether Lewis and William Clark, on the Yakima and Klikitat Rivers, was friendly all around.
Nomadic bands were led by nonhereditary chiefs with advisory powers. Before the historic period, the tribe created two divisions, eastern and western, of which the latter mixed with Cowlitz Indians west of the Cascades to become Taitnapams.
Skilled with firearms, the Klikitats sometimes acted as mercenaries for other Indian tribes, taking women and horses as pay. Their effort during the 1820s to expand south of the Columbia was repulsed by the Umpquas. Later, the Klikitats had their revenge by helping whites conquer the Umpquas. They also scouted for the U.S. Army in the 1850s.
In 1855, the United States asked the Klikitats and other local Indians, including the Yakimas, to cede 10.8 million acres of land. Most tribes accepted a 1.2-million-acre reservation in exchange. Although Indians retained fishing and gathering rights at their usual off-reservation places and were given at least two years to relocate, the governor of Washington declared their land open to non-Indians twelve days after the treaty council ended.
Angered by this betrayal, a few Yakimas killed some whites. When soldiers arrived, a large group of Indians drove them away. In retaliation for the treacherous murder of a Walla Walla chief and negotiator, the Walla Walla, Klikitat, Cayuse, and Umatilla Indians joined the Yakimas in fighting non-Indians. After the war ended and twenty-four of their number were executed, the Yakimas agreed to settle on a reservation in 1859. The future Yakima Indian nation included, in addition to Yakima bands, the Klikitats, Wanapams, Wishrams, Palus (Palouse), and the Wenatchis.
Reservation Yakimas entered a brief period of prosperity but were soon pressured to sell land; most people were forced into poverty, obtaining some seasonal work at best. In 1891, about one-third of the reservation land had been allotted to individuals, but the Yakima nation, under Chief Shawaway Lotiahkan, was able to retain the "surplus" usually sold to non-Indians in such cases. Still, many of the individual allotments, including some of the best irrigated land, were soon lost. Around the turn of the century as much as 80 percent of the reservation was in non-Indian hands.
As a result of twentieth-century dam construction (Bonneville in 1938, Grand Coulee in 1941, Dalles in 1956), the number of salmon and steelhead that returned to spawn in the Yakima River declined 98–99 percent. The issue of fishing rights remained an important and controversial one from the beginning of the reservation period through its resolution in 1974. Well into the twentieth century, Yakima nation people continued much of their traditional subsistence and ceremonial activities.