At the Edge

They’re small, they’re remote and many folks aren’t even aware they’re part of Florida.

They’re the Dry Tortugas, a group of islands located about 65 miles west of Key West, making them the last of the Keys as you follow them from the tip of the Florida peninsula. Juan Ponce de Leon encountered these islands during his 1513 voyage to Florida, making him the first European to make a record of them. He called them Tortugas, the Spanish word for “turtles,” because he and his crew saw plenty of them when they approached. The term “dry” was applied later by sailors because the islands had no springs or other sources of fresh water.

Gardner Key as seen from Fort Jefferson in the Dry Tortugas (1986).

Bush Key as seen from Fort Jefferson in the Dry Tortugas (1986).

In the 16th, 17th and 18th centuries, the Dry Tortugas were an important landmark for ships carrying silver from Spain’s colonial possessions in North America back to Europe, because they marked the entrance to the Florida Straits. Catching a boost from the powerful Gulf Stream, these ships would typically sail across the Gulf of Mexico, through the Florida Straits, up the Bahama Channel and into the Atlantic Ocean. This was a fast-lane route that sped up the voyage, but it was also dangerous. Pirates frequently harassed ships that passed through the Florida Straits, and violent storms could easily cause a ship to run aground on hidden reefs and shoals.

Excerpt of a map from around 1680 showing the Dry Tortugas at the western entrance to the Straits of Florida. Click on the image to view a zoomable version of the complete map.

Excerpt of a map from around 1680 showing the Dry Tortugas at the western entrance to the Straits of Florida. Click or tap the image to view a zoomable version of the complete map.

The Dry Tortugas got their first real survey during the brief period when Florida was a British colony (1763-1783). Surveyor George Gauld painstakingly measured the shape and area of the islands and the depth of the water at various points around them. His 1773 nautical chart, A Plan of the Tortugas and Part of the Florida Kays, became the standard guide for navigating in that neighborhood for more than half a century.

Even with Gauld’s maps, the waters around the Tortugas were still a difficult place for sailing by the time the United States acquired Florida in 1821. Pirates still looted passing ships that weren’t adequately armed, and wreckers descended upon shipwrecked boats to carry their cargo off to the British Bahamas to be sold. There were laws regulating this practice, but enforcing those laws was next to impossible in this remote, undeveloped section of the Florida territory. In 1822, the United States government purchased Key West to establish a military and civil government presence in the area. The U.S. Navy began patrolling the Florida Keys to combat piracy and unlawful wrecking, and by 1828 there was a federal court in operation at Key West.

Illustration from Harper's New Monthly Magazine depicting survivors of a shipwreck aboard a raft (1859).

Illustration from Harper’s New Monthly Magazine depicting survivors of a shipwreck aboard a raft off the Dry Tortugas (1859).

Several lighthouses were also established by 1826 to help mariners keep their bearings and avoid wrecking, including one on Garden Key in the Tortugas. This first lighthouse was a 65-foot brick tower with a fixed light. Shippers complained almost immediately that it was poorly located and too small to see. In 1856, Congress appropriated $35,000 to build a new lighthouse, but this time it would be taller–150 feet–and it would be located on Loggerhead Key where ships approaching from the west would be able to see it sooner and better. It would also have a first-order Fresnel lens, manufactured by L. Sautter and Company in Paris, France, a big improvement over the old light. The new lighthouse went into operation on July 1, 1858.

Excerpt of a nautical chart by the U.S. Coastal Survey showing the Dry Tortugas, including the original lighthouse on Garden Key (1851). Click or tap the image to view a zoomable version of the complete chart.

Excerpt of a nautical chart by the U.S. Coastal Survey showing the Dry Tortugas, including the original lighthouse on Garden Key (1851). Click or tap the image to view a zoomable version of the complete chart.

Another federal project got underway in the Dry Tortugas in 1846–a new fort from which to monitor shipping and commerce in the Gulf of Mexico and prevent potential enemies from seizing the Florida Keys in the event of a war. This would eventually be called Fort Jefferson, named in honor of President Thomas Jefferson. The fort, which still stands, is hexagonal in shape with outer walls 10 feet thick at the base, tapering to 8 feet at the top. The bricks were sourced from northern Florida; the granite blocks came from Maine.

Fort Jefferson was only half completed in 1861 when the American Civil War broke out, but Union troops rushed to occupy it anyway. Portions of the Florida Keys (including Key West) remained Union territory throughout the war, and the U.S. Army even raised a cavalry unit that included Floridians from the area.

Aerial view of Fort Jefferson (1984).

Aerial view of Fort Jefferson on Garden Key (1984).

Far removed as it was, Fort Jefferson didn’t see much military action during the Civil War, although it did serve as a prison both during and after the conflict. Prisoners of war and Union soldiers serving sentences for desertion and misconduct made up most of the prison population. Perhaps the most famous prisoners ever to occupy the fort were four of the individuals found guilty of conspiring to assassinate President Abraham Lincoln in 1865. One of the four, Dr. Samuel Alexander Mudd, was the physician who splinted John Wilkes Booth’s leg after he broke it jumping from the theater box where he had shot the president. While at Fort Jefferson, Dr. Mudd put his medical skills to work in the post hospital, although he lost that job for a time after he attempted to escape by stowing away on a departing ship, the Thomas A. Scott. When yellow fever broke out at the fort in 1867 and the prison doctor died, Mudd again filled in at the hospital. Some 300 soldiers at the fort, crediting Mudd as a lifesaver, petitioned President Andrew Johnson to pardon him. Johnson ended up pardoning all of the imprisoned conspirators except one, Michael O’Laughlen, who had died during the yellow fever outbreak.

Portrait of Dr. Samuel Alexander Mudd (1860).

Portrait of Dr. Samuel Alexander Mudd (1860).

Yellow fever, hurricanes and the obsolescence of Fort Jefferson’s walls led the Army to abandon the Dry Tortugas in 1874, although the Navy continued to store coal there for its ships to use. In fact, the Dry Tortugas were the last stop for the U.S.S. Maine before its fateful trip to Havana Harbor in 1898. The ship exploded and sank on February 15 of that year, killing most of the people aboard. American newspapers played up the idea that Spain had had something to do with the incident, which helped precipitate the Spanish-American War.

Wreckage from the U.S.S. Maine after it exploded and sank in Havana Harbor on February 15, 1898.

Wreckage from the U.S.S. Maine after it exploded and sank in Havana Harbor on February 15, 1898.

President Franklin D. Roosevelt declared Fort Jefferson a national monument in 1935, and Congress expanded the designation to include all of the Dry Tortugas in 1992. Despite its remote location, the park is open to the public and receives thousands of visitors annually. Visit the Dry Tortugas National Park website to learn more about how to reach this fascinating group of islands at the edge of Florida.

View of the Fort Jefferson lighthouse and Bush Key (1980s).

View of the Fort Jefferson lighthouse and Bush Key (1980s).