Penfield Reef Light, built in 1874, was one of the last masonry residence and tower lighthouses on a masonry foundation to be built in the United States, a design that was being replaced at the time by cast iron towers. The lighthouse is on the south side of Black Rock Harbor, at one end of a dangerous reef that extends to the southwest from Fairfield Beach into Long Island Sound. The reef, one of the most treacherous areas of the Sound, had earlier been marked by a can buoy, but increased commercial traffic in the area after the Civil War led to the construction of the lighthouse. The mansard-roofed design of Penfield Reef Light was also used fo several other lighthouses, like Sabin Point Light on the Providence River in Rhode Island. In 1969, the Coast Guard planned to replace the lighthouse with a steel tower, but a public outcry prevented this from happening. The Light was automated in 1971 and is still an active aid to navigation. In 2008, Beacon Preservation‘s bid to assume ownership of the lighthouse was approved under a program of the National Historic Lighthouse Preservation Act.