San Gerónimo Fort, San Juan

Fortín de San Gerónimo del Boquerón is a small fort located at the entrance of what is known today as Condado Lagoon. It was built during the 17th century to replace the smaller El Boquerón, which stood at the easternmost end of San Juan. The original Boquerón battery defended San Juan from attacks by Sir Francis Drake in 1595 and Sir George Clifford, 3rd Earl of Cumberland in 1598, who destroyed it after his attack.

San Gerónimo became part of San Juan's line of defense, along with San Antonio Fort/Bridge and Escambrón Fort and Castillo de San Cristóbal. It was listed in the National Register of Historic Places on October 11, 1983.

Unlike similar forts near Old San Juan, it is not part of San Juan National Historic Site. San Gerónimo is owned by the Institute of Puerto Rican Culture, but is managed by the Hilton. The hotel occasionally used it for private gatherings, but during recent times it has fallen into such disrepair that visitors are no longer allowed.