An earthen fortification on the hill to the northwest was built in 1863 as part of the defenses of the Confederate navy yard, iron works, and other war-related industries in nearby Columbus, Georgia. Designated Fort No. 5 on the plan done by the CSA engineers, the well-preserved fort has three cannon emplacements. It is pentagonal, with 90-foot sides. Escarpments are 30 feet. Trenches flank the central unit. During the attack by Federal troops under Major General James H. Wilson on April 16, 1865, the fort and other outer defenses were not manned because of a lack of Confederate manpower.