Unmanned reef lights of the Florida Keys

The unmanned reef lights are a system of automated navigation towers standing on screw-pile foundations throughout the Keys waterways and shallow areas. These structures mark submerged hazards and guide vessels safely through channels and reef passages.

The first of these navigation towers was built in 1921, with additional towers constructed through 1935 to support growing maritime traffic. These structures arose from the practical need to prevent shipwrecks and create safer passages through dangerous waters.

These navigation towers became symbols of how the Keys developed as a maritime crossroads, showing the relationship between infrastructure and seafaring communities. The structures reflect a practical approach to protecting trade routes that shaped regional identity.

The towers stand on remote reefs and shallow areas that are difficult to reach, so visitors typically view them from boats or at a distance with binoculars. Many host nesting birds, so keeping distance is important and the structures themselves are off-limits to public access.

Each tower features a distinct geometric shape, such as square, triangular, or hexagonal designs that were standardized by 1932 to create a visual language for sailors. This design system allowed captains to identify different reefs and hazard zones by shape alone without relying solely on light patterns.