The 56th Ohio Infantry Regiment was organized at Camp Morrow in Portsmouth, Ohio and mustered in for three years service On December 12, 1861, under the command of Colonel Peter Kinney.
[1] The regiment was attached to 3rd Brigade, 3rd Division, Army of the Tennessee, to July 1862.
2nd Brigade, 12th Division, District of Eastern Arkansas, Department of the Tennessee, to January 1863.
2nd Brigade, 12th Division, XIII Corps, Army of the Tennessee, to July 1863.
Defenses of New Orleans, Louisiana, Department of the Gulf, to April 1866.
The 56th Ohio Infantry mustered out of service on December 25, 1866, at New Orleans, Louisiana.
Expedition toward Purdy and operations about Crump's Landing March 9–14, 1862.
Movement on Bruinsburg, Mississippi and turning Grand Gulf April 25–30.
Moved to New Orleans December 17, then to Madisonville January 22, 1864, and duty there until March 1.