At the northern tip of Marrowstone Island in Washington, Fort Flagler State Park preserves the former Fort Flagler, a Coast Artillery post established in 1897 and activated in 1899 to help defend Admiralty Inlet, then regarded as the key naval gateway to Puget Sound. Paired with Fort Worden and Fort Casey, it formed part of a planned “triangle of fire” meant to deter or stop attack by sea. Named for Brigadier General Daniel Webster Flagler, the fort remained in military use until June 1953. Acquired as a state park in 1955, it retains historic military buildings and now blends coastal defense history with recreation and overnight lodging.