Fort Warren is used as an internment center for captured Confederate soldiers.

Over 1,200 captured Confederate soldiers and officials are housed here. They include Confederate Vice President Alexander Stephens, Henry Warfield and S. Teakle Wallis, as well as Confederate Commissioners James Murray Mason and John Slidell. The fort is also the location of a tragedy involving Melanie Lanier, the so-called “The Lady in Black.” The wife of prisoner Samuel Lanier, she dresses as a man and rows out to the island in an attempt to free her husband – only to kill him when she misfires her pistol as she tries to shoot prison commander Col. Justin Dimmick. Tried and sentenced to death, Lanier reputedly is allowed to don women’s clothes and is hanged. She reputedly haunts the island ever since.