The Decatur crossing of the Tennessee River was used extensively by Union forces. In the fall of 1863, elements of Major General William T. Sherman’s Army of the Tennessee passed through Decatur on their way from Vicksburg to Chattanooga. Union commands from the Army of the Tennessee spent the spring of 1864 camped at Decatur and were inspected by Major General James B. McPherson and Sherman on March 25, 1864. On March 8, 1864, Union Major General Grenville M. Dodge and the XVI Army Corps permanently occupied Decatur and constructed a pontoon bridge and substantial fortifications near the site of the bridge’s southern entrance in 1864-1865. After the Army of the Tennessee joined the Atlanta Campaign in late April 1864, a permanent garrison commanded by Colonel Charles C. Doolittle of the 18th Michigan Infantry, consisting of 1,500 infantry and seventeen pieces of artillery, was established there and was substantially reinforced in October 1864. The Federal army briefly withdrew the garrison to reinforce Nashville on November 23, but Decatur was reoccupied by Major General James B. Steedman and a division of U.S. Colored Troops on December 27, 1864. Decatur remained occupied by Union forces until the end of the war, and the last known date that Federal troops were there was June 30, 1865. After the war, Grenville Dodge went on to serve as Chief Engineer for the Union Pacific Railroad, responsible for the construction of the transcontinental railroad.