1971Twin Lights on Thacher Island were included on the National Register of Historic PlacesArts and Culture, Economy and Industry, Location and Setting, Buildings & Architecture, Maritime & Fishing Industry

The National Register noted that the lighthouses were “the last twin lights in existence in the United States. The Twin Lights on Thacher’s Island have been part of the seal of Rockport since that town was incorporated in 1840. Though only the southeast light remains in operation, both towers are Cape Ann landmarks.”