Hammond Castle is located on the Atlantic coast in the Magnolia area of Gloucester, MA. The castle, which was constructed between 1926 and 1929, was the home and laboratory of John Hays Hamond, Junior. The building is composed of modern and 15th-, 16th-, and 18th-century architectural elements and sits on a rocky cliff overlooking Gloucester Harbor. The castle operates as the Hammond Castle Museum, displaying Hammond's collection of Roman, medieval, and Renaissance artifacts as well as exhibits about his life and inventions.
Serving as a guide to ships entering the scenic and commercial Gloucester harbor from the Atlantic Ocean, this 36-foot tall cylindrical brick tower was built in 1832 and automated in 1986.