Coasts & Shorelines

boat approaching small island with a lighthouse
A small landing craft arriving at Little Brewster Island & Boston Light. The steel grey landing craft has white ropes hanging from both sides of the hull. Rippling blue water flows between the craft and a rocky island in the distance. A white lighthouse with thin black stripes rises from the island.

NPS Photo/Lampley

The Boston Harbor Islands National and State Park encompasses over 35 miles of coasts and shoreline on thirty islands and four peninsulas. These coasts and shorelines have been – and continue to be - constantly shaped and reshaped by physical processes. Wind, rain, ice, storm waves, and tides all sculpt these intermediary spaces between the mainland and the open ocean waters. The inner islands—such as Thompson, Spectacle, Snake, and Grape Islands— exist within comparatively quiet conditions, protected from the heightened wave and weather activity to which the outer islands—including the Brewster islands, Calf Island, and the Graves—are exposed.

Within the Boston Harbor you can find sandy and rocky beaches, coastal bluffs, salt marshes, developed shorelines, and more. A rich and ever-changing array of seaweeds (macroalgae), vascular plants, invertebrates, fishes, birds, and mammals are dependent on these important intertidal habitats.

Learn more about Intertidal and Subtidal Zones, Rocky Intertidal Zones, and Sandy Intertidal Shores

a rocky shoreline with an island in the distance
The coastline as seen from Rocky Neck at Worlds End, Hingham, MA. In the foreground a jagged grey rock sits above a small beach, composed of cobbles and small boulders. Patches of dark green seaweed (knotted wrack) cover the beach and can be seen in the water closest to shore. To the left a rocky bluff with cedar trees rises above the surf, with the lower sections of it colored black by a thin layer of cyanobacteria and algae. Across the water another island appears covered with broadleaf trees.

NPS Photo/Lampley

reddish brown rocky shore juts out into the deep blue waters. Three islands in the distance
A reddish brown rocky shore in the foreground juts out into the deep blue waters of the outer Boston Harbor. Many shallow rocks rise above the near shore water, surrounded by white foam. On the left side of the frame the foam is whipped up in the air as it crashes into nearshore rocks. Afar, the horizon stretches into the center frame, interrupted by three islands with exposed rocky bluffs and low green vegetation. Grey clouds hug the horizon, while a blue sky is visible at the top of the frame.

NPS Photo/Vincent

Last updated: November 2, 2021

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Boston, MA 02109


617 223-8666

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