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 Isla de Mona, PR    
Lighthouse best viewed by boat or plane.A hike of some distance required.
Description: Mona Island lies roughly halfway between the main island of Puerto Rico and the Dominican Republic, being about forty miles from each. This central location is how the island got its name, as the Taino Indians called it Amona, meaning “what is in the middle.” For many years prior to the construction of the Mona Island Lighthouse, vessels called at the island, which had no harbor, to pick up loads of bat guano that was mined in the island’s many caves. At times, there were between 300 and 400 workers on the island extracting the valuable guano that could be made into gunpowder and fertilizer.

Mona Island Light Station in 1945
Photograph courtesy U.S. Coast Guard
Two sets of plans were drawn up between 1885-1886 for a lighthouse on the eastern cape of Mona Island to help mark Mona Passage, which runs between Mona Island and Puerto Rico. One set of plans called for a second-class light with a range of twenty-two miles that would be displayed from an octagonal masonry tower rising to a height of seventy-five feet. The accompanying keeper’s dwelling was to be 124’ x 79’ and contain twenty-five rooms built around a central courtyard. This structure, with walls up to three feet thick, was intended to house three keepers.

Mona Island is composed of very porous and brittle sandstone, which made it unsuitable for such a massive structure. Instead, a second set of plans, also prepared by Rafael Ravena, was adopted that called for an iron tower positioned between two identical dwellings. This plan was approved in 1887, and work on the station commenced in the early 1890s.

The necessary materials were fabricated in France by Duclos & Cie. and then shipped to Mayagüez on the western coast of Puerto Rico. From Mayagüez, the building supplies were loaded on schooners and transported to Mona Island, where a steam launch was employed to shuttle the cargo between the schooners and the island. Two landing sites were used: one a mile from the construction site, and the second four miles distant. A narrow gauge track was laid on the island and a road carved out to move the materials across the island. Before work had progressed very far, events leading up to the Spanish-American War halted the effort around 1895. After the United States gained control of Puerto Rico in late 1898 at the end of the conflict, the Lighthouse Board decided that work on the lighthouse should be resumed. Money for constructing the lighthouse consisted of funds from the 1900 appropriation for repairs of lighthouses and from $60,000 set aside by an act of Congress on June 6, 1900 for the Puerto Rican lighthouse service.

The following paragraph on Mona Island was included in the Annual Report of the Lighthouse Board for 1899.

Mona Island, which is uninhabited, is about 6½ miles long and 5 miles wide, and is without a harbor. The vessels coming here for phosphate and guano anchor in the open roadstead. When storms arise from the eastward, the vessels, it is said, drop both their anchors and veer out all their chain cables. The crews than take to their boats and go ashore. In too many cases the vessels follow them. Within the last two years 11 such vessels were wrecked.

Mona Island Light Station in 1977
Photograph courtesy U.S. Coast Guard
A good portion of the building materials deposited on the island by the Spanish had been painted with red lead, which protected them from rust during the years the work was suspended. As some parts had still rusted and others were stolen or lost, a few new shipments of materials were required before the Mona Island Lighthouse was completed and then first activated on April 30, 1900.

The iron tower consists of a central cylindrical shaft braced laterally with lattice work. Inside, a spiral iron stairway leads upward to the twelve-sided lantern room, in which was installed a second-order Fresnel lens manufactured in France by Sautter, Lemonnier & Cie. The lens had six panels, three of them flashing ones, and was revolved by a clockwork mechanism powered by a 180-pound weight that descended through the central column of the stairway.

The keeper’s dwelling, built with steel plates and wooden framing, measures roughly 66’ x 33’ and is divided into seven rooms. A covered steel passageway connects the dwelling to the tower. Two additional structures on the site served as kitchens, and the station also had two cisterns: one near the dwelling, and a second about half a mile distant. The material for the second dwelling was placed in storage in 1900 and never used for that purpose.

Commander G.W. Metz was assigned to oversee the fifteen lighthouses of Puerto Rico in November of 1901, and he gave the following report on the Mona Island Lighthouse. "The station is the most isolated and unattractive one in this subdistrict, its shores being surrounded by reefs through which it is impossible to enter safely except at certain seasons of the year. It is farther out to sea than any other lighthouse under the charge of the Light-House Service.

Metz continued, "The place is so unattractive to the keepers that it is difficult to get anyone to go there. None of the keepers are willing to reside there m ore than two years. It is impracticable to secure the services of physician at this station in less time than four days, as Mayaguez, the nearest port, is forty miles distant and he has to make the trip there in a small sail boat. No one lives on the island except the light-house keepers and three or four peons - fishermen - and the soil is so poor and arid that little will grow except cactus and palm trees."

The light was electrified in 1938, and then automated in 1973. The lens was removed from the tower in 1976, the light was relocated to a position near the center of the island, and the U.S. Coast Guard abandoned the structures. The Department of Natural Resources of Puerto Rico currently controls the station.


  • Head: Castillo Manuel Perez (1914 - 1924), Octavio Segrada Rosado (1927 - 1928), Juan Ramos Ferran (1928 - 1933), Jose M. Velez (1933 - 1938), Pedro P. Roldan (1938 - 1945).
  • First Assistant: Jose P. Castillo (1912 - 1915), Agustin S. Cruz (1918 - 1921), Juan Ramos Ferran (1927 - 1928), Cayetano Valie (1928 - 1930), Jose M. Velez (1930 - 1933).
  • Second Assistant: Agustin S. Cruz (1918), Juan Ramos Ferran (1925 - 1927), Teofiio Fuertes (1929 - 1939).

Photo Gallery: 1 2 3


  1. “Faro de la Isla de la Mona,” Kevin Murphy, Historic American Engineering Record, August, 1984.
  2. Annual Report of the Lighthouse Board, various years.
  3. “Mona Island Lighthouse,” Sandra Shanklin, Lighthouse Digest, October, 2004.

Location: Located on the eastern shore of Isla de Mona, an island situated roughly 42 miles east of the main island of Puerto Rico.
Latitude: 18.0849
Longitude: -67.85139

For a larger map of Isla de Mona Lighthouse, click the lighthouse in the above map or get a map from: Mapquest.

Travel Instructions: Adventures Tourmarine is one of several tour operators that offer a Mona Island Expedition. The trip typically includes at least one night of camping on the beach and allows visitors time to hike to the lighthouse, explore caves, and experience the amazing marine life around the island. There is a landing strip on the northern end of the island near the campground, but planes apparently are no longer allowed to access the island so arriving by boat is the only way to get up close to the lighthouse.

The lighthouse is owned by the U.S. Coast Guard. Grounds open, tower closed.

Find the closest hotels to Isla de Mona Lighthouse

Notes from a friend:

Kraig writes:
Mona Island is known for its fantastic diving. While I didn't get the chance to experience the diving, the waters surrounding the island sure did look beautiful from the air.

See our List of Lighthouses in Puerto Rico

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Pictures on this page copyright Kraig Anderson, Library of Congress, used by permission.