The lower range light and the upper range light residence, 950 feet inland, were built by the U.S. Lighthouse Service in 1869. The upper range light also served as the lighthouse keeper's residence and is 15 feet taller than the lower tower. This enabled ships entering the harbor to align the lights at night and the towers during the day, preventing them from running aground on hidden reefs near the harbor entrance. The lanterns were originally fueled by lard or whale oil, then by kerosene and later by acetylene gas. Both range lights were converted to electricity and automatic controls in the early 1930s and were inactivated in 1969 when the single range light across the road was put into service.