The 104th New York Infantry was organized at Geneseo, New York beginning in October 1861 and mustered in for three years service on March 4, 1862 under the command of Colonel John Rohrbach. The regiment was attached to Wadsworth's Command, Military District of Washington, to May 1862. 2nd Brigade, 2nd Division, Department of the Rappahannock, to June 1862. 1st Brigade, 2nd Division, III Corps, Army of Virginia, to September 1862. 1st Brigade, 2nd Division, I Corps, Army of the Potomac, to March 1864. 1st Brigade, 2nd Division, V Corps, to June 1864. 1st Brigade, 3rd Division, V Corps, to August 1864. 2nd Brigade, 3rd Division, V Corps, to September 1864. Provost Guard, V Corps, to May 1865. 2nd Brigade, 3rd Division, V Corps, to July 1865. The 104th New York Infantry mustered out of service on July 17, 1865.
Detailed service
Left New York for Washington, D.C., March 22, 1862. Duty in the defenses of Washington, D.C., until May.
Expedition to Front Royal, Va., to intercept Jackson, May 28-June 1. Picket duty on the Shenandoah and at Front Royal until June 10.
Duty at Catlett's Station, Warrenton and Waterloo, Va., until August.
Pope's Campaign in northern Virginia August 16-September 2. Fords of the Rappahannock August 21–23. Thoroughfare Gap August 28. Groveton August 29. Bull Run August 30. Chantilly September 1.
Maryland Campaign September 6–22. Battles of South Mountain September 14; Antietam September 16–17.
Duty near Sharpsburg until October 30.
Movement to Falmouth, Va., October 30-November 19.
Campaign from the Rapidan to the James May 3-June 15. Battles of the Wilderness May 5–7; Laurel Hill May 8; Spotsylvania May 8–12; Spotsylvania Court House May 12–21. Assault on the Salient May 12. North Anna River May 23–26. Jericho Ford May 23. On line of the Pamunkey May 26–28. Totopotomoy May 28–31. Cold Harbor June 1–12. Bethesda Church June 1–3. White Oak Swamp June 13. Before Petersburg June 16–18. Siege of Petersburg June 16, 1864 to April 2, 1865. Mine Explosion, Petersburg, July 30, 1864.
Weldon Railroad August 18–21.
Reconnaissance toward Dinwiddie Court House September 15.
Warren's Raid on Weldon Railroad December 7–12.
Dabney's Mills, Hatcher's Run, February 5–7, 1865.
The regiment lost a total of 233 men during service; 5 officers and 81 enlisted men killed or mortally wounded, 2 officers and 145 enlisted men died of disease.
Commanders
Colonel John Rohrbach - discharged October 21, 1862 due to disability
