The regiment was attached to 2nd Brigade, 5th Division, XXIII Corps, District of Kentucky, Department of the Ohio, to July 1864.
4th Brigade, 1st Division, District of Kentucky, Department of the Ohio, to February 1865.
1st Brigade, Cavalry Division, District of East Tennessee, Department of the Cumberland, to July 1865.
The 12th Ohio Cavalry mustered out of service November 14, 1865, at Nashville, Tennessee.
Stoneman's Raid from Bean's Station, Tenn., into southwestern Virginia, December 10–29.
Stoneman's Raid into southwestern Virginia and western North Carolina March 21-April 25, 1865.