 Fort Flagler, a Washington state park, is situated on 784 acres (314 hectares) at the northern end of Marrowstone Island.It overlooks Port Townsend Bay and Admiralty Inlet, the entrance to Puget Sound.Fort Flagler was one of three forts, along with Fort Worden (near Port Townsend) and Fort Casey (on Whidbey Island), that guarded the entrance to Puget Sound.