Fort Pickens Fort Pickens is a pentagonal historic United States military fort on Santa Rosa Island in the Pensacola , Florida , area . It is named after American Revolutionary War hero Andrew Pickens . The fort was completed in 1834 and remained in use until 1947 . Fort Pickens is currently part of the Gulf Islands National Seashore , and as such , is administered by the National Park Service . History . After the War of 1812 , the United States decided to fortify all of its major ports , and as a result , French engineer Simon Bernard was appointed to design Fort Pickens . Construction on Fort Pickens lasted from 1829 to 1834 , with 21 . 5 million bricks being used to build the fort . Much of the construction was done by slave labor . 1858 fire . On the night of 20 January 1858 , the " USCS Robert J . Walker " was at Pensacola , when a major fire broke out at the Fort Pickens . The ship ' s men and boats , along with the hydrographic party of the U . S . Coast Survey steamboat USCS " Varina " , promptly assisted in fighting the fire . The next day , the commanding officer of the " Robert J . Walker " received a communication from Captain John Newton of the Army Corps of Engineers , commanding the harbor of Pensacola , acknowledging the important firefighting service rendered by the " Robert J . Walker " . The Civil War . By the time of the American Civil War , Fort Pickens had not been occupied since the Mexican - American War . Despite its dilapidated condition , Lieutenant Adam J . Slemmer , in charge of United States forces at Fort Barrancas , determined that Pickens was more defensible than any of the other posts in the area . His decision to abandon Barrancas was hastened when , around midnight of January 8 , 1861 , his guards repelled a group of local men intending to take the fort . Some historians suggest that these were the first shots fired by United States forces in the Civil War . Shortly after this incident , on January 10 , 1861 , the day Florida declared its secession from the Union , Slemmer destroyed over 20 , 000 pounds of gunpowder at Fort McRee , spiked the guns at Barrancas , and evacuated with 51 soldiers and 30 sailors to Fort Pickens . At Fort Pickens , on January 15 , 1861 and January 18 , 1861 , Slemmer refused demands for surrender from Florida militia Colonel William Henry Chase , who had designed and constructed the fort as a captain in the U . S . Army Corps of Engineers , and held the fort against Confederate threat of attack and until reinforced and relieved in April 1861 . Despite repeated Confederate military threats to it , Fort Pickens was one of the few Southern forts to remain in Union hands throughout the Civil War . The fort was also reinforced by troops and material sent by Montgomery C . Meigs . This Army engineer was tasked by President Lincoln and Secretary Seward to draw up a plan reinforcing Fort Pickens . Meigs was the Army engineer responsible for building the Washington aqueduct and getting the dome on the U . S . Capitol . Indian Wars . From October 1886 to May 1887 , the famous Apache Indian Geronimo was imprisoned in Fort Pickens , along with several of his warriors . Their families were held at Fort Marion . Endicott era . During the late 1890s and early 20th century , new gun batteries were constructed at Fort Pickens . These batteries were part of a program initiated by the Endicott Board , a group headed by a mid - 1880s Secretary of War , William C . Endicott . Instead of many guns concentrated in a traditional thick - walled masonry structure , the Endicott batteries are spread out over a wide area , concealed behind concrete parapets flush with the surrounding terrain . The use of the accurate , long - range weapons eliminated the need for the concentration of guns that was common in the Third System fortifications . One such battery , called Battery Pensacola , was constructed physically within the walls of Fort Pickens , while other similar concrete batteries were constructed to the east and west as separate facilities . The ruins of these later facilities are also included in the Gulf Islands National Seashore complex . Only one weapon of this era , a 6 - inch M1905 gun on a disappearing carriage located at Battery Cooper , survives to this day . On June 20 , 1899 , a fire in Fort Pickens ' Bastion D reached the bastion ' s magazine , which contained of powder . The resulting explosion killed one soldier and obliterated Bastion D . The force of the explosion was so great that bricks from Bastion D ' s walls landed across the bay at Fort Barrancas , more than 1 . 5 miles ( 2 . 4 km ) away . Nearby Fortifications . A companion fortification , Fort McRee , was located across Pensacola Pass from Fort Pickens on Perdido Key . Abandoned by Union forces and taken over by Florida and Alabama militia in January 1861 , it was badly damaged by Union bombardment during the American Civil War later that year . Abandoned by Confederate forces , Fort McRee remained battered and burned for the next three decades . Although subjected to improvements in the late 19th century during the run - up to the Spanish American War , the fort was struck by a hurricane 26 – 27 September 1906 that destroyed most of the newer structures that had been erected since 1898 . After the hurricane , only a minimal caretaker staff remained to ensure the security of the site and Fort McRee once again fell into disuse . Due to its location on a site accessible only by foot or boat , Fort McRee was left to the elements . Storms and erosion took their toll on the site and today , nothing more than a few scattered foundations remain . Fort Barrancas , which was built around previously constructed 17th - and 18th - century Spanish forts , as well as Fort Barrancas ' associated Advanced Redoubt approximately a mile ( 1 . 6 km ) to the northwest of Fort Barrancas , are located across Pensacola Bay from Fort Pickens on the grounds of what is now Naval Air Station Pensacola . At the same time the Union forces abandoned Fort McRee in 1861 , they also abandoned Fort Barrancas . This fort was also occupied by Florida and Alabama militia forces that were subsequently integrated into the Confederate forces . In May 1862 , after hearing that the Union Army had taken New Orleans , Confederate troops abandoned Pensacola and Fort Barrancas and the fort reverted to Union control .