The Citadel, a large ten sided brick and wood structure, once dominated the Fort's parade ground. Completed in 1825 as a defensive barracks, it was capable of housing 400 soldiers.
During the Union bombardment on August 22, 1864, the pine beams used in the construction of the citadel's roof caught fire and burned out of control. The fire forced the Confederates to dump approximately 60,000 pounds of cannon powder into the fort's water cistern to prevent it from exploding. On the morning of August 23rd, as the citadel continued to burn, Fort Morgan's garrison surrendered to Union forces.
After the surrender, portions of the Citadel walls were used as a source of brick for repairs to the damage sustained during the siege. The remaining remnants of the structure were razed in the 1880's and the debris used as a break water on the east end of Daulphin Island.