Indian Island Light stands at the south tip of Indian Island, the largest in a chain that helps shelter Rockport Harbor on Penobscot Bay. Established in 1850 when the harbor was a busy shipbuilding and lime-processing center, it served as the principal aid for vessels entering the harbor. The first light sat atop the keeper’s house, and a fourth-order Fresnel lens was added in 1856. Briefly deactivated in 1859, it resumed service in 1861. The present lighthouse dates from 1874–75. Sold by the United States Coast Guard in 1932, the light was deactivated in 1934 and is now a privately owned residence recognized on the National Register of Historic Places.