National reserve, northeastern Florida, U.S. Established in 1924 and covering 228 acres (92 hectares), it centres around a Spanish fort on Rattlesnake Island, 14 mi (23 km) south of St. Augustine .
Originating in 1569 as a wooden tower and completed in 1742, the fort is near the site of the slaughter of 300 French Huguenot colonists by Spaniards in 1565.