Fort Steilacoom's beginning started with the massacre at the Whitman Mission in 1847. An attack by the Cayuse murdered Dr Marcus and Narcissa Whitman plus eleven others. In response, the US Army established Fort Steilacoom in 1849.

Located near Lake Steilacoom, Fort Steilacoom became one of the first US Army's outposts north of the Columbia River. It was built to counter concerns with settlers about Native American uprisings.

During the signing of the Medicine Creek Treaty in 1854, nine local Native American tribes supposedly signed away their rights to their lands (King, Pierce, Lewis, Thurston, Mason and Gray's Harbor Counties). Chief Leschi, representing the Nisqually and Puyallup tribes, had led a group to the territorial capital of Olympia to claim that the reservation lands were unfit for crop production and removed them from necessary salmon rivers. The territorial Governor Stevens declared martial law. The Puget Sound War of 1855-1856 soon followed.

The US Army 9th and 4th Infantries were assigned to Fort Steilacoom during the Indian War. In one of the subsequent battles, volunteer US Army Colonel Abram Moses was killed. Chief Leschi was blamed for the murder and was eventually arrested, and brought to Fort Steillacoom as a prisoner of war.

After two trials, Chief Leschi was sentenced to death. Because he was a prisoner of war, Fort Steilacoom refused to carry out the execution. The territorial government in Olympia then passed a law allowing civilian authorities to carry out the death sentence. Chief Leschi was hanged in a meadow near Fort Steilacoom in 1858.

In 1859-1860, the 9th Infantry under the command of Captain George Pickett left for the San Juan Islands during the Pig War. In a boundary dispute with Great Britain, British naval superiority led to quick negotiations with each country stationed on opposing ends of San Juan Island.

In 1861, the US Army left Fort Steilacoom for the Civil War. The fort was decommissioned as a military post in 1868. In 1871, the buildings were re-designated as a territorial insane asylum. Currently, it houses Western State Hospital.

At Fort Steilacoom there is a free museum, open every first Sunday of each month from 1:00 to 4:00 pm (plus special events). Restoration is continuing as funds become available, donations gladly accepted. These four original remaining historic buildings (1857-8), museum and tour are certainly worthy of a visit. Please help support Historic Fort Steilacoom.