Construction began in 1787 at the directive of George Washington, and was completed on January 10, 1791. Whale oil lamps were originally used for illumination. In 1855 a fourth-order Fresnel lens was installed; that was replaced by a second-order Fresnel lens in 1864. That lens was replaced with an autobeacon in 1958.
During the American Civil War, raids on shipping in and out of Portland Harbor became commonplace, and because of the necessity for ships at sea to sight Portland Head Light as soon as possible, the tower was raised eight feet. Today, Portland Head Light stands 80 feet above ground and 101 feet above water, its white conical tower being connected with a dwelling. The 200,000 candlepower, second-order electric light, is visible from 16 miles away.