A Civil War Defense Line. Troops under Generals S. B. Buckner and A. S. Johnston, CSA, took up this key position in the Southern defense line on September 18, 1861. After Fort Henry fell and Fort Donelson was threatened, they evacuated Feb. 11-13, 1862. Gen. O. M. Mitchell and Federal troops entered Feb. 14, 1862, occupying the evacuated fort and securing the defense line for the North. Erected in 1962. For more information, see ExploreKYHistory: A Civil War Defense Line