During the Civil War, Louisville was an important supply depot for the Union army, and the Louisville & Nashville Railroad, which ran east of West Point, was vulnerable to Confederate attacks. To protect supplies at Louisville and the Union line of supply via the L&N Turnpike, Gen. W. T. Sherman built fortifications on the hill above West Point in late 1861. In Nov. 1861, the 9th Michigan Inf., led by Col. W. W. Duffield, built Fort Duffield, a 1,000 foot long earthen wall with 10 angles of fire. A number of men who died from disease or accident were buried on the hill south of the fort. In Feb. 1862, the 9th Mich. built a bridge across Salt River that became an important transportation route for Union operations in the area.