Battle of Perryville
In its first principal action of the war the regiment participated in the Battle of Perryville (also known as the Battle of Chaplin Hills) and suffered extensive casualties. The group set out from Louisville on 1 October 1862 under the direction of Maj. Gen. Don Carlos Buell and marched in pursuit of Confederate Gen. Braxton Bragg, passing through Taylorville, Bloomfield and Mackville before engaging in the Battle of Perryville on 8 October 1862. The 80th Illinois fell under the command of Brig. Gen. William R. Terrill (33rd Brigade) and Brig. Gen. James S. Jackson (10th Division). Both Terrill and Jackson were ultimately killed in the battle.