Fort pickens was built in 1834 as part of a plan to fortify the coastal areas from invasion after the war of 1812. Taking only 5 years to build with a total of 21.5 million bricks, the fort was the largest of those built to defend the Pensacola harbor.
The fort was one of the only forts in the south to remain in Union hands throughout the war, and this was mainly due to a man named Lieutenant Adam J. Slemmer. He was very much a Union loyalist and when Florida delcared its allegiance to the south on January 10th, 1861, Slemmer took it upon himself to sabotage the guns at nearby fort Barrancas, explode 20,000 pounds of gunpowder at fort McRee and escaped with 30 sailors and 51 troops to Fort Pickens.
After refusing to surrender to Confederate militia colonel William Henry Chase, who had actually designed the fort when he was in the U.S army, Slemmer held tight for 3 months until April 1861, when Colonel Harvey Brown arrived with reinforcements and supplies.
The fort was well made and apart from a few skirmish's wasn't directly attacked, and so remained in Union hands though out the war.
After this the fort was used as a prison in the Indian wars, and held one of the most famous Indian warriors known as Geronimo.
After this the fort was pretty quiet, with a number of smaller building projects taking place throughout the years, such as new gun platforms being built.
There are 2 notable tragedies that happened at the fort, and they were both fires. The first being on the night of the 20th January, 1858 when a fire destroyed many of the interior buildings, though no one was killed.
The next began on June 20th, 1899 when a fire broke out in the D bastion and slowly spread to the forts power magazine. It ignited 8000 pounds of gunpowder and killed one soldier.
You may notice a huge chunk of wall missing on the picture, well that's the section where the power store was, and the explosion was so big that bricks from the wall landed 1.5 miles away at Fort Barrancas.
Today the Fort is open as a tourist attraction and cared for by the National Park Service.
It would be safe to assume that spirits here would be that of past Union troops, since they occupied it for the longest time, but that doesn't seem to be the case. The most common ghost stories that come out of this place seem to involve the spirits of Native Americans.
The most common way in which they choose to manifest themselves is in the form of sounds, with people claiming to hear whispers and sometimes full conversations throughout all areas of the fort.
There are also claims of a strange presence in the area of where the wall blew up, with people being overcome with strong emotions of fear or panic.
Apart from this there are a few things such as a lot of orbs and mysterious things captured on EVP, but apart from that the ghosts here seem to be quite quiet.