Amelia Island Light, near the northern end of Amelia Island in northeastern Florida, guides vessels at St. Marys Entrance toward the St. Marys River, Cumberland Sound, and Fernandina Beach harbor, with a flashing white light that turns red over shoal water near Nassau Sound. Built in 1838 and first lit in 1839, it is Florida’s oldest existing lighthouse. Its brick tower reused materials from an earlier Cumberland Island light in Georgia. The tower was heightened in 1881, its original lamp system was replaced by a third-order Fresnel lens in 1903, and automation in 1970 ended resident keepers. The light remains active under Coast Guard oversight.