The original New London Harbor Lighthouse was built on the west side of the entrance to New London Harbor in 1760. It was removed when the current stone tower was built in 1801. In 1855 a fourth-order Fresnel lens replaced the original 11 lamps with 13-inch (330 mm) reflectors. Illumination was converted to oil-vapor lamp in 1909 and acetylene in 1912. The light was electrified in 1930. The present keeper's house was built in 1863.