Located at Ft. Jefferson on Garden Key, Dry Tortugas NP, FL
The Garden Key Light, also known as the Tortugas Harbor Light, is located at Fort Jefferson, on Garden Key in the Dry Tortugas, Florida. The first lighthouse, started in 1824 and first lit in 1826, was a brick conical tower. The lighthouse and its outbuildings were the only structures on Garden Key until construction started on Fort Jefferson in 1846. Construction continued until 1861, but was never completed.
In 1858 the Dry Tortugas lighthouse was built on a nearby island, and the first order Fresnel lens was moved there from the Garden Key lighthouse. The Garden Key lighthouse received a fourth order Fresnel lens, and became the harbor light for Fort Jefferson. In 1877 the brick tower was razed and replaced with a boilerplate iron tower on top of a stairwell in the fort (from Wikipedia - The Free Encyclopedia).