Castillo de San Marcos

Castillo de San Marcos, the oldest fort in the United States, was constructed between 1672 and 1695 by the Spanish living on Matanzas Inlet for the protection of the northern most outpost of the empire, Saint Augustine. Surrounded by a moat and constructed of a shell stone called coquina, the walls stand some 30 feet (9m) high and 12 feet (3m) thick. The massive Castillo serves as a clear reminder of the strength of the early Spanish colonial empire in the New World.

Previous wooden built versions of the fortress had not proved useful but the coquina constructed walls were tested and withstood attacks by a British force lead by James Moore only seven years after the fort's completion. Later in 1740, British General Oglethorpe fired cannon balls on the Castillo from Matanzas bay for 27 days without being able to penetrate the immense walls built out of the newly discovered coquina.

The Castillo played an important role in the Spanish-English struggle for the Southeast between 1650 and 1750. Beginning in 1763, the Castillo de San Marcos came under British control and remained so for twenty years until Great Britain ceded Florida to Spain at the end of the Revolutionary War in 1783.

The Castillo later served as a military prison after the U.S. acquired Florida in the Adams-On's Treaty of 1819. The name was changed by the Americans to Fort Marion. The Confederacy took control of the fort at the beginning of the Civil War without a fight. Union troops, in March of 1862, retook the fort after Confederate troops had withdrawn and the city of Saint Augustine and the fort were retaken, for the second time, without firing a shot. The fort was retired from active duty in 1899.

The twenty five acre site, located in historic downtown St. Augustine, was established as a National Monument in 1924. In 1942, in honor of its two and a half centuries of Spanish heritage, the name of the fort was changed back to the Castillo de San Marcos. The American Society of Civil Engineers designated the Castillo a Historic Civil Engineering Landmark in 1975. This popular tourist attraction is co-managed by National Park Service along with the Fort Matanzas National Monument.

The Castillo de San Marcos is open every day except December 25 from 8:45 am to 5:15 pm. For admission and additional information visit the National Park Service websites for the Castillo de San Marcos.