Derby Wharf Light is a small historic lighthouse at the end of Derby Wharf in Salem, Massachusetts, within Salem Maritime National Historic Site. Built in 1871, it marked the long waterfront wharf with a simple white square tower instead of the taller form of a major coastal beacon. Its station originally used an oil lamp and Fresnel lens, including one of only 17 sixth-order Fresnel lenses in the United States for many years. The light stands 25 feet above mean high water, is now solar powered, and remains maintained by the U.S. Park Service as a link between Salem’s working waterfront past and the preserved historic site.