210px-Mona_Island_LightPyramidal skeletal cast iron tower with central cylinder, lantern and gallery. Originally painted black, the lighthouse is now covered with rust. The active light  is on a 40 ft  steel tower.  The lighthouse has deteriorated severely since deactivation and is in danger of being lost.  The abandoned lighthouse has been added to the Lighthouse Digest Doomsday List.  The tower is “beyond repair.” The original 2nd order Fresnel lens, the largest lens ever used in Puerto Rico,  is in storage for eventual display at a proposed research and visitor center on the island. The Isla de Mona, part of the Commonwealth of Puerto Rico, is located in the Mona Passage between the Puerto Rican mainland and the Dominican Republic.

The Mona lighthouse entered service on April 30, 1900. It was constructed at the highest point of the island, near its eastern end, to guide navigation through the busy but dangerous Mona Passage. Rafael Ravena prepared two very different plans, one for a traditional masonry building with a central courtyard and twenty-five rooms, which would have been the most majestic lighthouse in the Caribbean, and the other for an iron tower flanked by two wood and metal buildings 64 feet long by 50 feet wide. Both designs would house three keepers.

The second option was chosen in November 1885 due of its lower cost, faster construction, and the suspicion that Mona’s porous substrate would not adequately support a large stone and brick building. The difficulty of transporting materials to Mona and other obstacles delayed construction so that at the end of the Spanish-American War only part of the material was onsite. The U.S. government obtained the remaining material and finished the project with a single residence. Although it is frequently stated that the tower was designed by Gustave Eiffel, which is possible because Eiffel designed a large variety of structures, no mention is made of the fact in Benjamin Nistal-Moret’s study nor in the well-documented work Faros Españoles de Ultramar.

The Mona lighthouse had the only second-order lens used in Puerto Rico, which projected its light 22 miles away; this lens is in Mona, disassembled and under the custody of the Department of Natural and Environmental Resources, which will display it in Mona’s future Center for Research and Visitors. The light was electrified in 1938 and automated in 1973. The building was finally abandoned in 1976 and since then the tower has deteriorated to the point of being beyond repair. Given its poor condition and remote location, it is likely that this lighthouse will never be restored.