Fort Pickens is a historical military site located within the Gulf Islands National Seashore. It was originally constructed in the late 1820s/early 1830s, with the purpose of protecting the entire Pensacola harbor - which at the time included the most signicant port east of the Mississippi and south of Baltimore. Completed in 1834, it remained in use until 1947. Fort Pickens is named after Andrew Pickens, militia leader from South Carolina and a hero of the War of American Independence.Interestingly, Fort Pickens remained in Union hands throughout the American Civil War.Note: in early September 2012, portions of the Gulf Islands National Seashore park were affected by Hurricane Isaac and closed due to large sand drifts on roads. You may want to check the official Park Service website if you are planning a visit.