Indian Island is an Unincorporated community in Jefferson County, Washington, United States. The whole island is covered by the Marrowstone CDP. It is located between Port Townsend Bay and Kilisut Harbor. Parts also border on Oak Bay and Scow Bay. Until the construction of the Port Townsend Ship Canal (also known as Portage Canal) Indian Island was connected to the mainland by a broad sand flat and backshore marsh. Indian Island is the location of the Indian Island Naval Reserve, which covers the entire island. No civilian residences are allowed on Indian Island. Indian Island is attached to Marrowstone Island, and is often grouped with it. Indian Island is served by the ZIP code for Nordland.