Alligator Reef Lighthouse

Alligator Reef Lighthouse Alligator Reef Lighthouse is 4 nautical miles east of Indian Key, off Islamorada, Florida Keys. The coordinates are: 24° 51′ 6.43″ N, 80° 37′ 7.86″ W S.

ABOUT:
Alligator Reef Light is located 4 nautical miles (7.4 km; 4.6 mi) east of Indian Key, near the Matecumbe Keys of Florida in the United States, north of Alligator Reef itself. The station was established in 1873. It was automated in 1963 and was last operational in July, 2014, and is being replaced by a 16' steel structure with a less powerful light located adjacent to it. The structure is

an iron pile skeleton with a platform. The light is 136 feet (41 m) above the water. It is a white octagonal pyramid skeleton framework on black pile foundation, enclosing a square dwelling and a stair-cylinder. The lantern is black. The original lens was a first order bivalve Fresnel lens. The light characteristic of the original light was: flashing white and red, every third flash red, from SW by W 1/2 W through southward to NE 1/8 E, and from NE by E 3/4 E through northward to SW 3/8 S; flashing red throughout the intervening sectors; interval between flashes 5 seconds. It has a nominal range of 14 nautical miles (26 km; 16 mi) in the white sectors and 11 nautical miles (20 km; 13 mi) in the red sectors. The new light will have a range of approximately 7 nautical miles (13 km; 8.1 mi). It is listed as number 980 in the USCG light lists. HISTORICAL INFORMATION:
The name honors the U.S. Navy schooner Alligator, part of the U. Navy Anti-Piracy Squadron that had recently been established in Key West, which went aground at this location in 1822. The Alligator was blown up after removing as much as possible from it to prevent it from being used by pirates. Countless vessels have also sunk here on the reef's jagged coral. This lighthouse cost $185,000 to build at that time. To support the tower, a 2,000 lb (900 kg) hammer was used to drive the 12" (300 mm) iron pilings ten feet (3 m) into the coral. Location 3.5 nautical miles; 6.4 kilometres (4 mi) east of Indian Key
near the Matecumbe Keys, Florida, United States

Coordinates: 24°51′6.43″N 80°37′7.86″W

Year first Lit: 1873

Foundation: Iron piles with platform

Construction: Wrought iron skeleton framework tower

Tower shape: Octagonal pyramidal tower enclosing stair cylinder, keeper's dwelling on a platform, balcony and lantern

Markings / pattern: White tower and keeper's dwelling, black lantern and pile foundations

Height: 136 feet (41 m)

Original lens: First order bivalve Fresnel lens (1873)

Current lens: VRB-25 aerobeacon (1997)

Light source: Solar power

Range: White = 16 nautical miles (30 km; 18 mi)
Red = 13 nautical miles (24 km; 15 mi)

Characteristic Fl (4) W 60s. (2Red sectors) 0.2s fl 9.8s ec. 0.2s fl 9.8s ec. 0.2s fl 9.8s ec. 0.2s fl

29.8s ec. Red from 23° to 249° and 047° to 068°. Racon "G" (Golf)

Admiralty number J2988

ARLHS number USA-006

USCG number 3-0980

Managing agent: United States Coast Guard

The end of the rainbow is at Alligator Reef Lighthouse. 🌊💙🌈  The "pot of gold" is the beautiful marine environment you'l...
10/07/2025

The end of the rainbow is at Alligator Reef Lighthouse. 🌊💙🌈 The "pot of gold" is the beautiful marine environment you'll find there. 🐟🐠🐡🦈🪸🐢💙
Please remember to protect our oceans when you visit amazing places like this and leave no trace.

09/13/2025

🌊💙🌊

09/02/2025
07/05/2024
06/30/2024

Featuring an amazing artist, Taylor Hale, who captures Alligator Reef Lighthouse so perfectly. 💙🌊

Carysfort, a neighboring lighthouse, just north of Alligator Reef Lighthouse, in Key Largo. Be very careful when boating...
06/30/2024

Carysfort, a neighboring lighthouse, just north of Alligator Reef Lighthouse, in Key Largo. Be very careful when boating there though. Lots and lots of shallow reefs all around the lighthouse. Beautiful area to snorkle with so much amazing sealife everywhere. 🩷

When Carysfort Reef Lighthouse was first built it had eighteen lamps in twenty-one-inch reflectors. However, in 1855, a magnificent first-order Fresnel lens made by Henry-Lepaute replaced the lamps for $22,000.

This change transformed the lighthouse's characteristic from a steady white light to a brilliant flash every thirty seconds. Additionally, in 1893, three red sectors were added to the light to mark hazardous areas.

📸 Courtesy of National Oceanic and Atmospheric Administration (NOAA)
Florida Keys Reef Lights

Address

78. 5 Mile Marker
Islamorada, FL
33036

Website

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