Assateague Lighthouse, at the Virginia end of Assateague, was first built in 1833 by the U.S. Treasury Department, but the original 45-foot tower was too low and dim to be effective, so it was rebuilt to 142 feet in 1867. Built on one of the island’s highest old dunes, the base of the brick tower stands 22 feet above sea level, and its red and white pattern distinguishes it from other tall historic brick lighthouses still functioning along the Atlantic Coast. It was placed to help navigators locate the heavily used Chincoteague Inlet, and although it now stands far inland, it originally stood near the end of the island facing the ocean before southward sand deposition after 1870 left it almost five miles from the inlet. Keepers tended oil-burning lamps for 100 years before electric flashing light replaced them in 1933, and the lighthouse became fully automated in 1963 with installation of the present rotating beacon. A first-order Fresnel Lens operated there from 1867 to 1963, using a complex series of glass prisms to reflect and concentrate light from a central source, while the present DCB-36 Rotating Beacon uses Fresnel-type lenses to focus light from a 1,000 watt lamp into a horizontal beam visible up to 22 miles away. Its characteristic is a double flash every five seconds.