- Where
- North-east Florida,
Atlantic coast, United States - Coordinates
- 29.8978° N
81.3114° W (the Castillo) - Founded
- 8 September 1565
(National Park Service) - The fort
- Begun 2 October 1672
first phase finished 1695 - Built of
- Coquina, a shell stone;
walls about 12 feet thick - Status
- National Monument
since 1924 - Best visited
- Spring and autumn
(National Park Service) - Advisory
- United States
(no State Department level)
A squat grey fort beside a warm harbour, with walls so thick that every doorway felt like a short tunnel. I knocked on one and found it was made almost entirely of tiny shells. Outside, narrow lanes of balconies, palms leaning over garden walls, and a horse and carriage taking its time. Downstairs, in the rooms where people had been held, I took my hat off and kept it off.
The short answer
St. Augustine is a city on Florida’s north-east Atlantic coast, about midway between Jacksonville and Daytona Beach, the National Park Service says. Pedro Menéndez de Avilés founded it for Spain on 8 September 1565 with about 800 settlers, and the Park Service calls it the first permanent European settlement in North America. Its landmark is the Castillo de San Marcos, a star-shaped fort of coquina stone begun in 1672, which the Park Service describes as the oldest masonry fortification in the continental United States and the only surviving seventeenth-century military construction in the country. The Castillo was made a National Monument in 1924 and has been in the Park Service’s care since 1933.
October 2019Cannon on the gun deck, with the bay and a sentry box beyond.
Photograph: Matthew Dillon via Flickr · Castillo de San Marco National Monument · CC BY 2.0
Why it's worth knowing
A fort that swallowed cannonballs. Coquina, the Park Service explains, formed from layers of the shells of the tiny coquina clam, cemented together over thousands of years by calcium dissolved out of the shells themselves; the word is Spanish for ‘tiny shell’. The Spanish quarried it on Anastasia Island, across the bay, burned oyster shells to make lime for the mortar, and, not knowing how the soft rock would stand up to artillery, built walls about 12 feet thick on average and up to 19 feet on the ocean side. When English forces from Charles Town bombarded the fort in 1702, the stone compressed instead of shattering, and the balls bounced off or sank in a few inches. The Park Service calls the Castillo one of only two forts in the world built of coquina; the other is Fort Matanzas, 14 miles south.
October 2019A vaulted casemate room, built of coquina.
Photograph: Matthew Dillon via Flickr · Castillo de San Marco National Monument · CC BY 2.0
A town older than its fort. The Castillo is the last of several forts on this shore; at least two wooden ones before it carried the same name, the Park Service notes, and the stone fort was begun only after pirates sacked the town in 1668 and the English settled Charles Town to the north. Menéndez’s landing party held a Mass of thanksgiving in 1565 and then a meal with the Seloy, who lived on the site, about 300 yards north of where the Castillo stands, at what is now the Mission of Nombre de Dios. Free and enslaved Africans came with Menéndez and worked on the first fortifications, the Park Service records.
The field notes
A dry moat for cattle
The Castillo’s moat was dug to stay dry, the Park Service explains: in an attack the townspeople sheltered inside the walls and their livestock grazed in the ditch. In November 1702, as English troops landed, a Spanish patrol stampeded 163 head of cattle through the English lines and down into the moat, Governor José de Zúñiga recorded. Almost 1,500 people took refuge inside the fort during that siege, which lasted 51 days, until a relief fleet from Havana arrived and the English withdrew, burning the town behind them. In 1740 James Oglethorpe of Georgia bombarded the Castillo for 27 days, and the walls held again. The Park Service later flooded the moat, for nearly 60 years; it is dry once more.
Four names for one fort
The Castillo never fell to an enemy in battle, the Park Service says; it changed hands by treaty. Britain took Florida under the Treaty of Paris of 1763 and called the building Fort Saint Mark. When the United States took possession in 1821 it became Fort Saint Marks, which clashed with another old Spanish fort of the same name near Tallahassee, so on 7 January 1825 an Army order renamed it Fort Marion. It was still Fort Marion when President Coolidge made it a National Monument in 1924, and in 1942 Congress restored the original Spanish name.
Prisoners at Fort Marion
In its Fort Marion years the fort became a prison for Native Americans. In 1837 the US Army held Osceola and about 200 other Seminoles there as prisoners of war. From 1875 to 1878 it held 74 prisoners from five tribes of the Great Plains: 33 Cheyenne, 27 Kiowa, 11 Comanche, 2 Arapaho and 1 Caddo. In 1886 the Army crowded 502 Chiricahua Apache into a fort with room for about 150, most of them in tents on the gun deck; the Army physician recorded 24 deaths, 16 of them children, and 103 children were taken from the fort to the Carlisle Indian Industrial School in Pennsylvania. The Park Service now holds annual gatherings at the fort with the Cheyenne and Arapaho Tribes, the Kiowa Tribe, the Comanche Nation and the Caddo Nation, and tells these years as part of the monument’s history.
Fort Mose and Fort Matanzas
Under a Spanish royal decree, enslaved people who escaped from the English colonies to the north could find freedom in Florida, and in 1738 Governor Manuel de Montiano granted the freedom seekers land about two miles north of St. Augustine to build their own settlement and fort, Gracia Real de Santa Teresa de Mose, the Park Service records; it describes the settlement as the first legally established free African settlement in North America. Nothing of its earth and wooden buildings remains, but the site is now Fort Mose Historic State Park. Fourteen miles south of the town, Fort Matanzas, built of coquina in 1740 to guard the southern approach, is a National Monument of its own, and like the Castillo it was never captured.
October 2019A sentry box on the gun deck, with Matanzas Bay behind.
Photograph: Matthew Dillon via Flickr · Castillo de San Marco National Monument · CC BY 2.0
October 2019The way in: the gate passage through the ravelin, the bay visible beyond.
Photograph: Matthew Dillon via Flickr · Castillo de San Marco National Monument · CC BY 2.0 · cropped
Matanzas Bay from the fort's shore, with the Bridge of Lions in the distance.
Photograph: Philip Davis via Unsplash · Unsplash licence · cropped
The Bridge of Lions across Matanzas Bay.
Photograph: Brandon Schmidt via Unsplash · Unsplash licence
- Walk the old lanes early, before the day begins in earnest, while the shopkeepers are still sweeping their steps.
- Take the list up onto the gun deck and add the view. Hold on to it. The wind off the water would very much like to add the list to the harbour, and nearly managed it.
- Knock on a wall, gently, and then look closely at what it is made of.
- Eat something outdoors under a balcony, and take a long time over it.
- Some of the rooms in the fort held prisoners. Go into them quietly, and stay as long as they ask.
A block of coquina in the Castillo’s wall. Coquina is a soft shell stone, Spanish for ‘tiny shell’, formed from layers of coquina clam shells cemented by calcium dissolved from the shells themselves, the National Park Service explains. The Spanish cut it on Anastasia Island and laid it in walls about 12 feet thick; under English cannon in 1702 it compressed instead of shattering, and the balls bounced off or sank in a few inches. It stays in the wall.
Tally, in the marginI rapped on it the way one raps on any wall, and it was a good while before I looked closely and saw it was made of small shells, more than I could count, all holding on to one another. I have knocked more politely ever since.
Getting there
How to get there. Jacksonville, to the north, and Daytona Beach, to the south, both have international airports close to Interstate 95, the Park Service notes, and rental cars are available there and in St. Augustine. From I-95, exit 318 (State Road 16) leads to US 1 and the old town. The Castillo is on A1A at the north end of the historic district; the City of St. Augustine runs a paid car park in front of it and a parking garage a short walk away, off West Castillo Drive. The old town itself is a place to walk.
When to go. Spring and autumn are the mildest seasons, the Park Service says, with temperatures often around 70 to 80°F (21 to 26°C); summers are hot and humid, with frequent afternoon thunderstorms, and winters are generally cool to mild. The fort is quietest from mid-September to mid-November and busiest around Christmas and New Year, in school holidays and at weekends, and school groups are many in October and November and from February to May.
What to arrange ahead. Little: the Castillo opens every day but Thanksgiving and Christmas Day, with first admission at 9 am and last at 5 pm, and charges an entrance fee listed on the Park Service’s fees page. Rangers give short talks, and on some days there are musket or cannon demonstrations; the gun deck closes during thunderstorms, and there is no elevator to it, so the Park Service offers a virtual tour of the closed and upper areas.
Safety. The State Department’s travel advisories cover other countries, so none applies here. The Park Service closes the gun deck in lightning and recommends sun protection and plenty of water in summer, and reminds visitors that June to November is hurricane season. The National Hurricane Center gives the Atlantic season as 1 June to 30 November; its outlook of 25 October 2026 expected no tropical cyclone to form in the following seven days. Coastal flooding is a hazard of its own: on 25 October 2026 the National Weather Service in Jacksonville warned of significant coastal flooding around high tide on the north-east Florida beaches until 28 October, with numerous roads that may close. The Park Service also posted on 21 July 2026 that work to replace, raise and rehabilitate the park’s seawalls would begin on 27 July 2026, with the fort open throughout and some areas outside it closed.
Mark this place
Common questions
How old is St. Augustine?
St. Augustine, on Florida’s Atlantic coast, was founded for Spain by Pedro Menéndez de Avilés on 8 September 1565, with about 800 settlers, the National Park Service says. The Park Service calls it the first permanent European settlement in North America.
What is the Castillo de San Marcos made of?
The Castillo de San Marcos in St. Augustine is built of coquina, a soft limestone made of the shells of the tiny coquina clam cemented together, quarried on Anastasia Island. The National Park Service says its walls average about 12 feet thick and reach 19 feet on the ocean side, and that the stone compressed under cannon fire instead of shattering.
How old is the Castillo de San Marcos?
Governor Manuel de Cendoya broke ground for the Castillo de San Marcos in St. Augustine on 2 October 1672, and the first phase of building was completed in 1695, the National Park Service records. It calls the fort the oldest masonry fortification in the continental United States.
Was the Castillo de San Marcos ever captured?
No. The National Park Service says the Castillo de San Marcos in St. Augustine never fell to an enemy in battle: it withstood English sieges in 1702, of 51 days, and in 1740, when James Oglethorpe bombarded it for 27 days, and passed to Britain only by the Treaty of Paris of 1763.
Why was the Castillo de San Marcos called Fort Marion?
After the United States took Florida in 1821, the Castillo de San Marcos in St. Augustine became Fort Saint Marks, the same name as another old Spanish fort near Tallahassee. To end the confusion an Army order of 7 January 1825 renamed it Fort Marion, the National Park Service records; Congress restored the Spanish name in 1942.
Who was imprisoned at Fort Marion?
The US Army held Native Americans at Fort Marion, now the Castillo de San Marcos in St. Augustine: Osceola and about 200 other Seminoles in 1837, 74 prisoners from five Plains tribes from 1875 to 1878, and 502 Chiricahua Apache in 1886, the National Park Service records.
What was Fort Mose?
Fort Mose, properly Gracia Real de Santa Teresa de Mose, was a settlement and fort about two miles north of St. Augustine, granted in 1738 by Spanish Florida’s governor to people who had escaped slavery in the English colonies. The National Park Service calls it the first legally established free African settlement in North America; the site is now Fort Mose Historic State Park.
When is the best time to visit the Castillo de San Marcos?
The National Park Service gives spring and autumn as the mildest seasons in St. Augustine, with temperatures often around 70 to 80°F, and says the Castillo de San Marcos is quietest from mid-September to mid-November. Summers are hot and humid with afternoon thunderstorms, and June to November is hurricane season.