Alligator Reef Light, Pile lighthouse near Indian Key, Florida, US.

Alligator Reef Light is a white octagonal pyramid skeleton framework of iron, 136 feet tall, raised on black iron pilings driven into the coral north of Alligator Reef, 4 nautical miles east of Indian Key. The frame encloses a square dwelling and a stair cylinder, with a black lantern on top. A 16-foot steel beacon with a weaker light stands beside it.

The structure got its name from a Navy schooner that ran aground on the reef in 1822. Operations started in 1873 to help ships find safe passage through the complex waterways.

The name comes from the U.S. Navy schooner Alligator, which ran aground on the reef in 1822 and was blown up to keep it from pirates. The tower is listed as number 980 in the USCG light lists. Since 2021, the Islamorada group Save Alligator Lighthouse has held title and raised $6 million for restoration.

The tower stands in open water 4 nautical miles east of Indian Key, so it can only be reached by boat; there is no dock or landing on the structure. The active aid is now a 16-foot steel light next to the old tower, with a range of about 7 nautical miles. The old iron tower is not open to visitors.

The tower's 12-inch iron pilings were driven ten feet into the coral with a 2,000 lb hammer, and the build cost $185,000 in 1873. In 2021 the Islamorada group Friends of the Pool, later renamed Save Alligator Lighthouse, was granted title and raised $6 million; solar-powered lights were illuminated in October 2023.