[2] It was built on a rise 20 feet (6.1 m) above the Fort Vancouver fur trading station established by the Hudson's Bay Company (HBC).

However, the agreement permitted Great Britain's Hudson's Bay Company to continue operation throughout the territory, including at Fort Vancouver.

[3] Congress wished to provide military power to facilitate the removal and control of the regions' native peoples and promote settlement of the Pacific Northwest by white Europeans.

[3] These wars targeted a number of indigenous groups including the Cayuse, Shasta, Tutuni, Klickitat, Nisqually, Puyallup, Yakama, Spokane, Coeur d'Alene, Paiute, Bannock, Modoc, Nez Perce, Shoshone, and Muckleshoot, among others.

[3] During these wars, the Vancouver Barracks functioned as an administrative center, station for troops, training ground, supply depot, and prison.

[3] Groups of Native Americans were incarcerated as prisoners of war, in preparation of relocation to reservations, or as a precaution to protect white settlements.

In World War II when Vancouver Barracks was used as a staging area for the Seattle Port of Embarkation, the post included 3,019 acres (12.22 km2), and had billeting space for 250 officers and 7,295 enlisted persons.

The majority of billeting space was later transformed into military offices and became home to the 104th Division of the Army Reserve, plus Washington National Guard units as well.