Established in 1856 by Lieutenant Colonel Edward Steptoe, Fort Walla Walla played a pivotal role in the military history of the Pacific Northwest during the volatile Indian Wars of the mid-to-late 19th century. Positioned strategically to secure the Oregon Trail and assert federal control over the Inland Empire, the fort served as a major U.S. Army outpost during key regional conflicts, including the Yakima and Nez Perce wars. Originally constructed as a temporary stockade, it evolved into a permanent cavalry post by the late 1870s. The historic district preserves a remarkably intact collection of late-19th-century military architecture, including the 1858 commander's quarters-believed to be the oldest continuously occupied military residence in the state-alongside officer's row, barracks, and parade grounds that reflect the daily life and strategic operations of the frontier military.

Following its deactivation as an active military post in 1910, the site transitioned into a vital medical resource for veterans, reflecting the nation's changing priorities after World War I. In 1921, the property was transferred to the Bureau of War Risk Insurance, which quickly evolved into the Veterans Administration (VA). This transition led to the adaptation of historic military structures and the construction of new Colonial Revival-style hospital facilities to serve injured servicemen. Today, the Fort Walla Walla Historic District stands as a dual testament to frontier military history and the evolution of federal veterans' healthcare, preserved through the active VA Medical Center and the adjacent Fort Walla Walla Museum.