Unmanned reef lights of the Florida Keys, Unmanned reef navigation lights in the Florida Keys, United States

The Unmanned Reef Lights of the Florida Keys are automated navigation towers built on screw-pile foundations in the shallow waters and reefs of the Keys. They mark submerged hazards and guide vessels through the channels and reef passages of this stretch of coastline.

The first two towers, Molasses Reef Light and Pacific Reef Light, were built to the same plan as square pyramidal towers in 1921. A standardized hexagonal pyramidal design followed in 1932, used for Smith Shoal and Tennessee Reef lights in 1933 and Cosgrove Shoal and Pulaski Shoal lights in 1935. These aids were designed to be automated from the start, unlike older lighthouses then being automated.

The towers are a familiar sight for anyone traveling by boat through the Keys and are seen as landmarks of these waterways. Fishermen and sailors still use them as reference points, even though modern navigation tools are now common.

The towers stand on remote reefs and are not open to the public, so the best way to see them is from a boat or with binoculars from a distance. Many serve as nesting sites for birds, so keeping a respectful distance is always a good idea.

The Hen and Chickens Shoal Light, the smallest of the group, was the only one built as a triangular pyramidal tower; it survives as a daymark with its lantern removed. The standardized hexagonal design of 1932 was used for Smith Shoal and Tennessee Reef in 1933, then Cosgrove Shoal and Pulaski Shoal in 1935.