The oldest surviving screw-pile lighthouse in the United States, an 1852 iron skeleton painted red, standing over reef that…The oldest surviving screw-pile lighthouse in the United States, an 1852 iron skeleton painted red, standing over reef that drops from 2m to 20m. Elkhorn and pillar coral, big schools, and far fewer boats than Molasses a few miles south. Named for HMS Carysford, wrecked here in 1770. Lit in 1852 and built by Lieutenant George Meade. Its keepers reported the reef 'boiling with fish'. Deactivated in 2014; corrosion has since put it on preservation watchlists. The reef below has been a coral restoration focus for decades. Anchorage: Sanctuary mooring buoys. Day run from Key Largo. Hazards: The structure is severely corroded and closed, never attempt to land or climb. Plus