Fort McHenry was instrumental in defeating the British land and naval forces on September 12, 1814 during the War of 1812.
The fort would became known as the “Baltimore Bastille” for its time utilized as a Confederate prison camp. During the course of the U.S. Civil War about 2,000 political prisoners were held, including the Baltimore Mayor, the Baltimore Police Commissioner, a former Maryland Governor, 28 newspapermen and 31 members of the Maryland Assembly that were sympathetic to the Confederacy. An additional 2,000 Confederate soldiers, from the battles of Anthiem and Gettysburg, were held within Fort McHenry.
On July 1863, after the Battle of Gettysburg, a total of 6,957 individuals were held at Fort McHenry. That was the highest amount of prisoners kept at the fort, during the war, before they were transferred to other prisons.
The American Battlefield Trust lists other Civil War Prison Camps, including the infamous Belle Isle Prison, which was located on an island near Richmond, Virginia.