February 16, 2022 - Fort DeSoto,
St. Petersburg, Florida

We drove out to Fort De Soto, which in on a key out in the middle of the entrance to Tampa Bay.  There are five offshore keys: Madelaine Key, St. Jean Key, St. Christopher Key, Bonne Fortune Key and the main island, Mullet Key. The keys are connected by either bridge or causeway.

In 1529, the Spanish explorer Pánfilo de Narváez investigated the barrier islands after his expedition landed between St. Pete Beach and Clearwater, Florida. Ten years later, Hernando De Soto came ashore somewhere near the southern part of Tampa Bay, beginning what would culminate in the conquest of Florida for the Spanish Empire.

In 1849, a detachment of US Army engineers, including future Confederate General Robert E. Lee surveyed the area. They recommended Mullet and Egmont Keys become fortified as appropriate site for coastal defense installations. Both keys could only be reached by boat as they were completely separated from the mainland. Although the US Government did not build any fortifications on the two keys, they did station Union Army troops there during the American Civil War. Their purpose was to aid in the Union naval blockade of Tampa Bay, with the Egmont Key lighthouse acting as an observation tower.

However, fortifications were not built on them until the Spanish–American War.  The main operation on Mullet Key was named Fort De Soto in 1900, in honor of Hernando de Soto.

These posts were to contain batteries of artillery and mortars to protect Tampa Bay from any invading forces. Construction of Fort De Soto began in November 1898 and was completed in 1906. The foundation was constructed of a seashell concrete formula, and the walls and ceiling used a seashell, stone, and concrete mix. The fort contained artillery and 12-inch coast defense mortar batteries, Batteries Laidley and Bigelow. The post consisted of 29 buildings. The post's features included a large barracks, a hospital, a guardhouse, a blacksmith and carpenter shop, an administration building, and mess hall with kitchen, a bakery, and a storehouse. The site also had brick roads, concrete sidewalks, and a narrow-gauge railroad to aid in moving materials and supplies around the post.

Fort De Soto was active from 1898 to 1910. At least one company was present at Fort De Soto at all times and many times several units were present. Mosquitoes were a constant problem and the post was very hot in the summers. In 1910, most of the Army troops were moved from Fort De Soto to Fort Morgan, Alabama. Only a caretaker force remained; by 1914, only an ordnance sergeant and game warden remained at the post.

In November 1922, the Army announced it would inactivate both Forts De Soto and Dade.   By 1926, the forts had been disarmed except for four 12-inch mortars of Battery Laidley at Fort De Soto, which remained under caretaker status. The forts were meant to be reactivated and rearmed in time of war, but that never occurred.

In June 1941, the federal government bought back Mullet Key from Pinellas County for $18,404. As planned, It was turned into a sub-post of MacDill Field and used as a bombing range throughout World War II.

In 1962, a toll road, the Pinellas Bayway (formerly State Road A19A, now SR 682), was completed to the mainland, enabling island visitors to arrive by car. On December 21, 1962, Fort De Soto Park opened.  On December 2, 1977, the Fort De Soto batteries were placed on the National Register of Historic Places. The four 12-inch M1890 mortars and two 6-inch Armstrong guns at Fort De Soto are the only weapons of their type remaining in the United States.