Castillo de San Marcos National Monument
1 Castillo Drive South
St.Augustine, FL 32084-3699

Phone: 904-829-6506

Construction of this, the oldest masonry fort in the continental United States, was started in 1672 by the Spanish to protect St.Augustine, first permanent settlement by Europeans in the continental United States, 1565. The floor plan is the result of modernization work done in the 18th century.