Muscle Ridge (sometimes known as Mussel Ridge Shoals) is and extinct plantation, now an unorganized territroy (township) in Knox County on a set of low islands in the Gulf of Maine. Muscle Ridge Plantation was organized in 1852, and reorganized in 1878, and 1904. Muscle Ridge surrendered its plantation organization in 1916, and has since remained unorganized territory. Recently there have been no year around residents. 
- ↑ Muscle Ridge Township, Knox County, Maine in Maine Genealogy (accessed 23 June 2013).
- ↑ Maine Historical Records Survey Project, Division of Professional and Service Projects, Work Projects Administration, Counties, Cities, Towns, and Plantations of Maine: a Handbook of Incorporations, Dissolutions, and Boundary Changes (Portland, Maine: The Survey, 1940), 88 (digital p. 97). A digital version is available via a link in the FHL Catalog.