The Spanish erected the lighthouse, officially lit on May 2, 1882, on the spot judged, in 1782, by Fray Iñigo Abbad y Lasierra, writer of the first formal history of Puerto Rico, as "the reference point of those who regularly navigate these islands." Inside, facing the main entrance, a corridor leads to an eight-step stairway ascending into the lighthouse tower. An elaborate, richly decorated cast-iron stairway leads to the stone central lantern. The original illuminating apparatus, not changed until after 1898, had an 18-mile range and displayed a fixed white light which every three minutes flashed red. This neo-classic structure appears castle-like with the parapet in the portico's roof and with the tower's rectangular cornice in the middle section. In 1975, the Conservation Trust of Puerto Rico acquired 316 acres of land, including the lighthouse, to establish Las Cabezas de San Juan Nature Reserve.
The Spanish erected the lighthouse, officially lit on May 2, 1882, on the spot judged, in 1782, by Fray Iñigo Abbad y Lasierra.