Fort Zachary Taylor The Fort Zachary Taylor State Historic Site , better known simply as Fort Taylor ( or Fort Zach to locals ) is a Florida State Park and National Historic Landmark centered on a Civil War - era fort located near the southern tip of Key West , Florida . History of Fort Zachary Taylor . 1845 - 1900 . Construction of the fort began in 1845 as part of a mid - 19th century plan to defend the southeast coast through a series of forts . The fort was named for United States President Zachary Taylor in 1850 , a few months after President Taylor ' s sudden death in office . Yellow fever epidemics and material shortages slowed construction of the fort , which continued throughout the 1850s . At the outset of the U . S . Civil War in 1861 , Union Captain John Milton Brannan seized control of the fort , preventing it from falling into Confederate hands and using it as an outpost to threaten blockade runners . Originally , the fort was surrounded by water on all sides , with a walkway linking it to the mainland . The fort was completed in 1866 , although the upper level of one side was destroyed in 1889 to make way for more modern weapons , with the older cannon s being buried within the new outer wall to save on materials . The fort was heavily used again during the 1898 Spanish - American War . 1900 - present . In 1947 , the fort , no longer of use to the army , was turned over to the U . S . Navy for maintenance . In 1968 volunteers led by Howard S . England excavated Civil War guns and ammunition buried in long - abandoned parts of the fort , which was soon discovered to house the nation ' s largest collection of Civil War cannon s . Fort Taylor was therefore placed on the National Register of Historic Places in 1971 , and designated a National Historic Landmark in 1973 . Due to the filling in of land around the fort , including the creation of an attractive stretch of beach , the park now occupies 87 acres ( 352 , 000 m² ) . Truman Annex . The fort ' s land that is closer to downtown Key West became part of the Truman Annex to Naval Air Station Key West . The annex was originally called Naval Station Key West until its closure in 1974 and included a submarine base . President Harry S . Truman used it for his Winter White House for 175 days in 11 visits . The Secret Service had a private beach built on the land for the president ' s security , but he reportedly only visited it once , preferring the public beaches . The beach name is called " Truman Beach " The fort , along with its related support buildings , was later renamed for Truman . Naval Station Key West was decommissioned in 1974 because the U . S . Navy had decommissioned nearly all of their diesel - electric submarines and contemporary nuclear powered submarines were too big for the existing port . Most of the then - former naval station became an annex ( Truman Annex ) to the remaining Naval Air Station Key West and served as the landing point for many during the 1980 Mariel boatlift of Cuban refugees . Those buildings in the Truman Annex and associated real estate not retained by the navy as part of NAS Key West were sold to private developers . There ' s a museum for the Truman White House and the navy continues to own and maintain the piers and that portion of the naval station property to the south of Fort Taylor , primarily in support of Joint Interagency Task Force South ( JIATFS ) and the Naval Security Group Activity . Current uses . In addition to the role of the fort and its adjacent beach as tourist attractions , Fort Taylor is also the location of a number of annual events , including week - long Civil War reenactment s . On the weekend preceding Halloween , it is transformed into a haunted fort , much like a haunted house but on a grand scale and with a distinctive Civil War theme .