Columbus, Kentucky was the northernmost Confederate position on the Mississippi River and was known as the "Gibralter of the West" for its extensive fortification and a massive steel chain stretched across the river to Belmont, Missouri. Fearing that the Union advance on New Madrid, Missouri around thirty miles downstream would cut him off, Confederate General Leonidas Polk ordered an evacuation and over the next week moved all his men and 140 cannon to the New Madrid area. Union forces took possession of Columbus on March 3, 1862. (By John Osborne)
David G. Martin, The Shiloh Campaign, March-April 1862 (Cambridge, MA: Da Capo Press, 2003), 40.