The 85th New York Infantry was organized at Elmira, New York beginning in August 1861 and mustered in for three-years service on December 2, 1861 under the command of Colonel Uriah L. Davis.

The regiment was attached to 3rd Brigade, Casey's Division, Army of the Potomac, to March 1862.

3rd Brigade, 3rd Division, IV Corps, Army of the Potomac, to June 1862.

Wessell's Brigade, Division at Suffolk, VII Corps, Department of Virginia, to December 1862.

1st Brigade, 1st Division, Department of North Carolina, to January 1863.

1st Brigade, 4th Division, XVIII Corps, Department of North Carolina, to May 1863.

District of the Albemarle, Department of North Carolina, August 1863.

Unattached, XXIII Corps, Department of North Carolina, to June 1865.

Moved to Fort Monroe August 16–23, then to Suffolk, Va., September 18, and duty there until December.

Expedition to Williamston and Gardiner's Bridge July 5–7 (detachment).

Duty at Albemarle Sound and Chowan River until November.

Regiment reorganized January 1865, and duty in the Department of North Carolina until June.

Duty in the Department of North Carolina until June.