Such an approach avoided St. Augustine's primary defense system, centered at Castillo de San Marcos.

[7] Convicts, slaves, and troops from Cuba were used as labor to erect the structure, which was sited on present-day Rattlesnake Island[8] and had a commanding position over Matanzas Inlet.

[13] The marshy terrain was stabilized by a foundation of pine pilings[7][14] to accommodate a building 50 feet (15 m) long on each side with a 30-foot (9.1 m) high tower.

When the United States took control of Florida in 1821,[19] the fort had deteriorated to the point where soldiers could not live inside.

By 1924, three vertical fissures in the wall were repaired and the structure was stabilized;[25] in the same year, National Monument status was proclaimed.

The Fort Matanzas National Monument Headquarters and Visitor Center, located at 8635 A1A about 15 miles (24 km) south of St. Augustine, Florida, was built in 1936.

Located on Anastasia Island, it services the Fort Matanzas National Monument, a five-minute boat ride away.

of Plans & Design in what is called National Park Service Rustic architectural style, and includes a museum.

[26] Additional designed features include flagstone walkways and sidewalks, an exterior staircase, a retaining wall, parking areas and roads and curbs.