Perryville Union order of battle

The following Union Army units and commanders fought in the Battle of Perryville of the American Civil War. Order of battle compiled from the army organization during the battle and return of casualties. The Confederate order of battle is listed separately.
Army of the Ohio.
MG Don Carlos Buell, Commanding
MG George Henry Thomas, second in command
Escort:
Signal detachment: Cpt Jesse Merrill
I Corps.
MG Alexander McDowell McCook
II Corps.
MG Thomas Leonidas Crittenden
Escort:
III Corps.
MG Charles Champion Gilbert