Carysfort Reef Light is located on Carysfort Reef east of Key Largo, Florida. The lighthouse has an iron-pile foundation with a platform, and a skeletal, octagonal, pyramidal tower, which is painted red. The light was 100 feet (30 m) above the water. It was the oldest functioning lighthouse of its type in the United States until it was decommissioned in 2015, having been completed in 1852. The light last installed was a xenon flashtube beacon. It was added to the National Register of Historic Places in 1984.