The longest and happiest chapter in the history of Mullet Key is the one with no soldiers in it. For more than sixty years the island that was built to repel a fleet has been a park, and a deeply loved one, drawing millions of people a year to the same sand the mortars once guarded. The fort never won a battle, but the place around it won something better in the end: a second life as one of the finest public beaches in the country.
The first attempt to turn Mullet Key into a resort came before the park we know. When the Army let the old fort go, Pinellas County bought a tract of the island in 1938 and tried to make a getaway of it. A Captain Charles R. Carter sank some eight thousand dollars into converting a building into a fishing lodge, and in January 1939 the county leased two old buildings on the south end, structures the Mullet Key quarantine station had once used, to a man named Percy L. Roberts. The terms, reported in the St. Petersburg Times, were fifty dollars a month for the first year and a hundred for the next two; Roberts would run a daily boat to the island, serve fish dinners, and rent fishing tackle, his dock sitting near the old Bee Line ferry, some ten miles off across the lower bay. It was a modest, hopeful little enterprise, and the war swept it away. In June 1941 the federal government bought the key back and turned it into a bombing range.
The park's real beginning came after the Second World War. In 1948 Pinellas County repurchased Mullet Key, along with the cluster of small adjacent islands, for $26,495.54, and county officials immediately declared the whole of it a public recreation area open to all. Excursion boats began running out to the island. But what truly made it a park was not a boat; it was a road. In 1962 the state completed the Pinellas Bayway, the toll road that finally tied the island to the mainland and let families simply drive to the beach. Fort De Soto Park opened on 21 December 1962, and on 11 May 1963 it was formally dedicated, in perpetuity, as a public park. The fortress had become a destination.
Over the following decades the park grew into the largest in the Pinellas County system, roughly eleven hundred and thirty-six acres spread across five connected keys, Madelaine, St. Jean, St. Christopher, Bonne Fortune, and Mullet itself. Its reputation grew with it. In 2005 the coastal scientist Stephen P. Leatherman of Florida International University, the geologist known nationally as “Dr. Beach,” who ranks hundreds of American beaches each year against some fifty criteria of sand, water, safety, and setting, named the park's North Beach the number one beach in the United States; in 2009 the travel site TripAdvisor likewise rated it the country's top beach. The accolades rest on real infrastructure: two fishing piers, the thousand-foot Gulf Pier and the five-hundred-foot Bay Pier, a two-hundred-and-thirty-eight-site campground, miles of paved trail, a boat launch, ferries to Egmont Key and Shell Key, and a coastline that draws somewhere around two and a half to three million visitors a year. The same isolation that once made the key a lonely posting now makes it a refuge.
The park has been a good steward of the fort it is named for. On 2 December 1977 the Fort De Soto batteries were placed on the National Register of Historic Places, protecting the surviving mortar battery and its grounds. In 1999 the park rebuilt the lost Quartermaster Storehouse, a building that had originally served as the post exchange, reconstructing it from old photographs, the Army's own engineering condition reports, and other government records, with the work funded by the volunteer group Friends of Fort De Soto together with the county parks department. That reconstructed storehouse is now the park's history museum, where the Spanish-American War origins, the garrison, and the wartime bombing range are told for the visitors who come for the beach and stay for the story. The same volunteer stewardship that rebuilt the storehouse keeps the wider history of the key alive.
There is a fitting resolution in all of this. Mullet Key was fortified for a war that never reached it, garrisoned by men who fought mostly the mosquitoes, and armed with guns that were obsolete before they were mounted. Its true and lasting purpose turned out to be peace. The great mortars are a backdrop for picnics now; the deep channel they were trained on is a place to watch dolphins roll and freighters slide out to the Gulf; the island's restless sand, which took Battery Bigelow and is taking Fort Dade, simply gets raked and enjoyed. As a fortress Mullet Key was a failure that never had to prove itself. As a park it has outlasted and outshone every use the military ever found for it.