Muscle Ridge Islands is an archipelago and unorganized territory off the coast of South Thomaston in Knox County, Maine, United States.

[1] The population was 9 at the 2020 census.

[2] According to the United States Census Bureau, the unorganized territory has a total area of 49.7 square miles (128.6 km2), of which 0.95 square miles (2.45 km2) is land and 48.7 square miles (126.2 km2) is water (98%).

[3] The archipelago includes over a dozen islands, including Andrews, Dix, Fisherman, Pleasant, Graffam, and Two Bush Island, which is home to the Two Bush Island Light.

This Maine state location article is a stub.