Don Carlos Buell
April 6–7, 1862. The Department of the Ohio was converted to the Army of the Ohio in March 1862. Don Carlos Buell led this Army until he was relieved of command after the Battle of Perryville in October 1862. The Shiloh Union order of battle indicates that the 9th was a part of William "Bull" Nelson's Fourth Division and William B. Hazen's 19th Brigade after the conversion.