The prison and guardroom were constructed from 1856 to 1860. The guard room on the left quartered the guard detail, while the prison confined enemy prisoners of war and soldiers who broke military law. Both buildings were built of Georgia brown brick. The interior had white plaster walls and fireplaces. The high ceilings and large doors and windows kept the rooms comfortable in the warm weather. The rooves were made of slate shingles. These were the first two fort buildings completed.