Upper Columbia River Route
The Upper Columbia River Route was an early branch of the Oregon Trail. About a day's ride (on horseback) west of the Whitman Mission stood the Hudson's Bay Company post Fort Nez Perces. It was a supply post for trappers, traders, and American emigrants. Emigrants "put in" on the Columbia River at the HBC post and floated down river to The Dalles. The River Route was often treacherous, many lost their belongings, a few lost their lives. Some chose to follow the river along the southern shore. They avoided the water's danger, they found other difficulties along the rocky and narrow bank.
Although the route traveled by Lewis and Clark and the Corps of Discovery in 1805 was unnamed, it can be easily argued that they were the first Anglo-Americans to travel the Upper Columbia River Route. The Corps of Discovery followed the Snake River to its confluence with the Columbia (at present Kennewick, Washington), a dozen or so miles upriver from the Walla Walla's confluence.
The river's currents carried the Corps of Discovery through the river's regions. They described in detail the flora and fauna and the tribes who made this area home. Their descriptions provided enough information to inspire others to follow their lead into the Pacific Northwest, first by English and American trappers and traders, then by overland emigrants.
In the 1810s, Wilson Price Hunt, an employee of the Pacific Fur Company (the Astorians), led an overland expedition which also passed through the area near the Walla Walla's confluence with the Columbia and proceeded on the river to the Pacific Fur Company's post, Fort Astoria.
The West's explorers and mountain men traveled over the route later known as the Upper Columbia Route, including Nathaniel Wyeth, Benjamin Bonneville, Joe Meek, and Robert Newell. The Americans claimed the route as their own from 1841 on.