The Rock Harbor Lighthouse is a light station located in Rock Harbor on Isle Royale National Park, Michigan. It was listed on the National Register of Historic Places in 1977. The Rock Harbor Lighthouse is a 50-foot-tall cylindrical tower with a 16-foot-diameter base, constructed of randomly placed stone and brick, capped with an octagonal beacon with a cop…The Rock Harbor Lighthouse is a light station located in Rock Harbor on Isle Royale National Park, Michigan. It was listed on the National Register of Historic Places in 1977. The Rock Harbor Lighthouse is a 50-foot-tall cylindrical tower with a 16-foot-diameter base, constructed of randomly placed stone and brick, capped with an octagonal beacon with a copper roof. A one-and-a-half-story keeper's house with gabled roof is connected to the tower on one end.