Fort Nez Percés, sometimes also spelled Fort Nez Percé (with or without the accent) and later known as (Old) Fort Walla Walla was a fortified fur trading post on the Columbia River on the territory of modern-day Wallula, Washington. It was in operation from 1818 until 1857.
The location was chosen for its strategic geographic value. The nearby Walla Walla Valley had long been an important rendezvous point for parties working several peripheral fur districts. The 1815 decision to refocus the entire New Caledonia region southward to the Columbia River meant greatly increased traffic on the river. Furthermore, Donald MacKenzie intended to open up the Snake River country, adding another operation converging on the area where Fort Nez Percés was built. Essentially all company exports and supplies passed through the Columbia Gorge. The location of Fort Nez Percés at the eastern end of this trunk line to the ocean made it the most important post in the interior. In addition, increasing tensions with the local indigenous Indians necessitated a permanent fortified post. Finally, the area was significant to the Indians themselves. Not only was it a major meeting and trading ground, but it was where Lewis and Clark had first met the Columbia River peoples and had made an informal treaty of friendship.
The fort was built with a double palisade, unique among North West Company forts. The inner wall was high and made of sawed timber. The storehouse and dwellings were within. Trade was conducted via a small hole in the inner wall. The outer palisade was made of planks high and thick, and topped with a range of balustrades. There were four towers at each of the fort's corners, and these each contained large water tanks for fighting fire. Soon after it was built, Alexander Ross said it was "the strongest and most complete fort west of the Rocky Mountains, and might be called the Gibraltar of the Columbia."
Ross became the first chief factor of the fort.
On October 5 1841, shortly after a visit by Charles Wilkes' expedition, the fort was destroyed by fire and was subsequently rebuilt out of adobe bricks. The fort was again burnt down at the beginning of the Yakima War in 1855. It was rebuilt a second time, but was eventually abandoned in 1857 when the Hudson's Bay Company gave up its business in the Oregon Territory and relocated its headquarters in the Northwest from Fort Vancouver to Fort Victoria.