Haunted places guide · St. Augustine, Florida

Castillo de San Marcos: The Ghosts of America's Oldest Masonry Fort

Spanish soldiers built it from seashell stone, and it has never been taken by force. For more than three centuries it has also been a prison. This is the Castillo’s true history, the ghost stories told along its walls, and how to see it by day and after dark.

By The Haunted Rooms Team · Updated November 2026 · How we rate places

3.8/5Haunted Rooms Score

1672Construction begins

1695Core completed

Our nearest ghost hunt: Battleship North Carolina Meet the ghosts

The Castillo de San Marcos stands on the western shore of Matanzas Bay in St. Augustine, a low grey star of coquina stone with a diamond-shaped bastion at each corner, a dry moat and a sloping lawn running down to the water. Spain began it in 1672 to protect the colony and the treasure route along the Florida coast, and it is the oldest masonry fort in the continental United States. Since 1933 it has been run by the National Park Service as a national monument.

It is also a fixture of every ghost walk in the city. Guides tell of a Spanish soldier on the walls at dawn and dusk, a light in a watchtower that has no power supply, cold rooms in the casemates and the face of the Seminole leader Osceola, who was held here in 1837. The fort has appeared on Ghost Adventures and Monumental Mysteries. This guide separates the history from the legends and tells you how to visit.

Castillo de San Marcos at a glance

3.8/5
Haunted Rooms Score

Haunted reputation4

History5

Ghost hunter access2

Open to the public

Address 1 S Castillo Dr, St. Augustine, FL 32084
Built 1672 to 1695, of coquina quarried on Anastasia Island
Other names Fort St. Mark (British, 1763 to 1783), Fort Marion (American, from the 1820s to 1942)
Run by National Park Service; national monument since 1924
Most haunted spots The casemates, the gun deck at sunset and the watchtowers
Best-known stories A Spanish soldier on the walls, the watchtower light, Osceola
Ghost hunting Not allowed; the fort closes at 5:15 PM and night ghost walks stay outside

Our nearest ghost hunt: Battleship North Carolina Visit / tours

History of the Castillo de San Marcos

St. Augustine had been defended by a series of wooden forts in its first century, and in the 1670s Spain decided to build in stone. Work began on October 2, 1672. The stone was coquina, a soft rock made of tiny shells bonded together, quarried on Anastasia Island and ferried across the bay, and most of the hard labor was done by Native American workers from the Spanish missions. The core of the fort was finished in 1695, with four bastions named San Pedro, San Agustin, San Carlos and San Pablo.

The choice of stone proved inspired. When Carolina governor James Moore laid siege in 1702, the English cannonballs sank into the coquina instead of shattering it, and the people of St. Augustine sheltered inside the walls for about two months until a Spanish fleet from Havana broke the siege. In 1740 James Oglethorpe’s British forces bombarded the fort for 27 days and then tried to starve it out, but supplies still came in by river and he withdrew. The Castillo was never taken by force. It changed hands only by treaty, becoming the British Fort St. Mark in 1763, Spanish again in 1784, and American in 1821.

The Americans renamed it Fort Marion, and for much of the 19th century its rooms served as a prison. In October 1837 the Seminole leader Osceola was seized under a flag of truce and held here before being moved to Fort Moultrie in South Carolina, where he died. That November his fellow prisoner Coacoochee escaped through a high window and down a rope into the moat, a story that became part of the fort’s lore. Another prisoner, Uchee Billy, died at the fort in 1837.

From 1875 the fort held Kiowa, Cheyenne and other Plains Indian prisoners under Richard Henry Pratt, and the drawings some made here in ledger books are now prized as Ledger Art. In 1886 and 1887 about 491 Chiricahua and Warm Springs Apache men, women and children, members of Geronimo’s people, were confined here in harsh, crowded conditions; at least 24 died and were buried at North Beach. Geronimo himself was sent to Fort Pickens near Pensacola.

The fort became a national monument in 1924 and passed to the National Park Service in 1933. Congress restored its Spanish name in 1942, and it was listed on the National Register in 1966. More than 600,000 people visited in 2022.

The ghosts of the Castillo de San Marcos

The soldier on the walls

The most repeated story is of a uniformed Spanish soldier seen pacing the ramparts or gazing out to sea at sunrise and sunset, the hours when the garrison would have changed the watch. Old Town Trolley’s guides and many walking tours tell it, and it is the image most people take home from St. Augustine’s ghost walks. There is no record behind it, but there is no shortage of men who served and died here over three centuries.

The light in the watchtower

Ghost tour guides also tell of a dim light glowing in one of the corner watchtowers on stormy nights, though no power runs to it. You can test this one yourself from the bayfront seawall after dark.

Osceola

Visit St. Augustine’s own ghost guide repeats the most macabre legend: that the face of Osceola has been seen floating near the fort, wearing an expression of anguish. Osceola did not die here: he was moved to Fort Moultrie in South Carolina, and what happened to his remains happened there. This is folklore attached to the place where he was held.

Cold rooms and camera images

Visitors describe sudden chills, a feeling of being watched and nausea in the vaulted rooms, especially the one tour guides call the dungeon, and night photographers report orbs and misty shapes. News4JAX suggests checking your night photos. Remember that the fort sits on the bay, where humid air and floodlights make mist and lens effects common.

Where to look

The casemates: the vaulted coquina rooms around the courtyard, used as storerooms, quarters and later prison cells.
The gun deck: the top of the walls, best at sunset when the soldier is said to walk.
The corner watchtowers: the round sentry boxes on the bastions, including the one said to glow on stormy nights.
The moat and glacis: open to walk until midnight, and the best place to stand after dark.
The bayfront seawall: for a view of the fort lit up at night, and the route most ghost walks follow.

Visiting the Castillo de San Marcos

The Castillo is open every day except Thanksgiving and Christmas. The first admission is at 9 AM and the last at 5 PM, and visitors must leave by 5:15 PM. There is an entrance fee for the fort itself; check the National Park Service website for current rates and for living history and cannon firing demonstrations. The gun deck closes during thunderstorms.

The grounds around the fort stay open until midnight, closing from midnight to 6 AM. That means you cannot go inside after dark and no ghost hunting is allowed, but you can walk the moat and the bayfront at night. Most of St. Augustine’s walking ghost tours and the Ghosts and Gravestones trolley pass the fort, and the Park Service has occasionally offered candlelight tours.

Visiting National monument open daily; grounds closed midnight to 6 AM
Hours and season Daily 9 AM to 5:15 PM, last entry 5 PM; closed Thanksgiving and Christmas
Ghost hunting No: night ghost walks pass outside the walls only

Tips for your visit

Go inside in the late afternoon, then stay on the grounds for sunset, the soldier’s hour.
Join an evening ghost walk that starts near the City Gate; most include the fort.
Bring a lens cloth: the bay air fogs cameras and makes orbs.
The Huguenot Cemetery and the Old City Gate are a two-minute walk away.
Treat the Apache and Seminole history with respect; people suffered here.

Go ghost hunting nearby

Visiting a haunted place by day is one thing. Investigating one after dark is another. On a Haunted Rooms ghost hunt our team takes you through a historic building with professional ghost hunting equipment, runs EVP sessions and vigils, and gives you time to explore on your own. These are the nearest ones we run.

USS Battleship North Carolina Ghost Hunt and Tour, Wilmington: investigate below decks on the World War II battleship moored across the river from downtown Wilmington, from 8 PM to 2 AM.
Old Moore County Jail and Old Lynchburg Funeral Home Ghost Hunt, Tennessee: two haunted buildings in one night: the 1893 county jail and the old funeral home across the street, from 8 PM to 2 AM.
Thomas House Hotel Ghost Hunt and Sleepover, Red Boiling Springs, Tennessee: dinner, an after-hours ghost hunt and a night in one of Tennessee’s best-known haunted hotels.

See all Florida ghost hunts

More haunted places nearby

St. Augustine Lighthouse: Florida’s most haunted lighthouse, with night tours inside
Haunted hotels in St. Augustine: stay a few blocks from the fort
The Casablanca Inn: the bayfront inn of the lantern lady
Haunted places in Florida
Haunted places in St. Augustine

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Frequently asked questions

Is the Castillo de San Marcos haunted?

It is one of St. Augustine’s most famous haunted places. Ghost tours tell of a Spanish soldier on the walls, a light in a watchtower with no power and cold rooms inside. These are stories rather than records, but the fort has more than 300 years of soldiers, sieges and prisoners behind it.

Was Osceola held at the Castillo?

Yes. The Seminole leader was captured under a flag of truce in October 1837 and held at the fort, then called Fort Marion, before being moved to Fort Moultrie in South Carolina, where he died.

Can you visit the Castillo at night?

Not inside. The fort closes at 5:15 PM, but the grounds are open until midnight and most ghost walks pass by. The Park Service has occasionally run candlelight tours.

Was the fort ever captured?

No. It withstood the sieges of 1702 and 1740 and changed hands only by treaty, between Spain, Britain and the United States.

What is coquina?

A soft limestone made of compressed shells, quarried on Anastasia Island. It absorbed cannonballs rather than shattering, which is why the fort survived its sieges.

Can you go ghost hunting at the Castillo?

No. It is a national monument and investigations are not allowed. Our nearest ghost hunts are listed on this page.

Sources

Facts on this page are checked against the official website, historic records and news coverage. Ghost stories are reported as staff, visitors and investigators tell them, and we say where records contradict a story.

About the authors

The Haunted Rooms Team runs public ghost hunts and overnight investigations at historic venues across the United States. We research every place in our guides using official sites, historic registers, local archives and news coverage, and we report ghost stories as the stories they are. We review each guide regularly so you are not sent to a place that has closed, changed hands or banned visitors. Spotted something out of date? Let us know.