Fort Duwamish (1855-1856) - Established in 1856 at the Seattle settlement as a blockhouse during the Yakima Indian War (1855-1856).
Established soon after the siege of Seattle (26 Jan 1856) during the Yakima Indian War. A single blockhouse known as Fort Decatur (1) protected the Seattle settlement during the siege. The siege was unsuccessful but the threat of a larger force of hostile Indians caused the settlers to build a second blockhouse on the south side and connect these two blockhouses with a series of breastworks and stockades. This second blockhouse was known as Fort Duwamish. No further attacks occurred.
Fort Duwamish was a two-story blockhouse of unfinished logs, 22 feet square. The top floor was set so the corners overlapped each side of the bottom floor. After the war ended in 1856 the blockhouse was used until 1862 as the first Duwamish school.