Marrowstone is located at (48.058323, -122.687943). According to the
United States Census Bureau, the CDP has a total area of 6.3 square miles (16.4 km2), all of it land. Prominent land features include: • Marrowstone Point, at the northern end of Marrowstone Island; • Kinney Point, at the southern end of the island; • Nodule Point, on the east side, mid island; • Mystery Bay, an inlet on the western side of Marrowstone Island; • Griffiths Point, on the western side of Mystery Bay; • East Beach, a sandy beach at the northern end of East Marrowstone Road; and • Scow Bay/Kilisut Harbor, which separates Marrowstone Island from its western neighbor, Indian Island, a
Navy ammunition depot. • the narrow causeway which used to connect the southwestern end of Marrowstone Island with the southern end of Indian Island was removed and replaced by a low bridge in 2022-2023. This was done to create passage for salmon into Scow Bay and beyond. Opening the cut restored the passage that used to exist. A short, higher bridge joins the western side of Indian Island to the mainland of
Jefferson County.
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.
Mystery Bay State Park is another state park on Marrowstone Island, located on 10 acres (4 hectares) of Mystery Bay shorefront about a half-mile north of the Nordland General Store. It is primarily for boaters.
Kinney Point State Park comprises at the south end of the island. Accessible only by boat, it is part of the
Cascadia Marine Trail. Flagler Road (SR 116) runs along the western edge of Marrowstone Island, which is primarily low-lying. East Marrowstone Road runs along the eastern edge of the island, which consists largely of sandy bluffs, with the exception of the area near East Beach. The Nordland General Store is Marrowstone's only source of
groceries. It is arguably the focal point of Marrowstone; on maps the town of Nordland (the address of all Marrowstone residents) is usually located at the site of the Nordland General Store. It can be found just across Flagler Road from Mystery Bay, near the center of Marrowstone Island. Severely damaged by fire in November of 2020, it was forced to close for an extended period before re-opening in 2024 as a community-owned co-op. ==Demographics==