Although transferred to the 5th, the two former 12th New York companies remained on duty at corps headquarters. Detailed service Moved to Washington, D.C., May 29, 1861. Duty in the defenses of Washington, D.C., until July 16, 1861. Advance on Manassas, Va., July 16–21. First Battle of Bull Run July 21. Upton's Hill August 27. Duty in the defenses of Washington, D.C. until March 10, 1862. Advance on Manassas, Va., March 10. Moved to the Virginia Peninsula March 22–24. Warwick Road April 5. Siege of Yorktown April 5-May 4. Before Yorktown April 11. Reconnaissance up the Pamunkey May 10. Reconnaissance to Hanover Court House May 26. Battle of Hanover Court House May 27. Operations about Hanover Court House May 27–29. Seven Days before Richmond June 25-July 1. Battle of Gaines's Mill July 27. White Oak Swamp and Turkey Bend June 30. Malvern Hill July 1. Duty at Harrison's Landing until August 16. Movement to Fort Monroe, then to Centreville August 16–28. Pope's Campaign in northern Virginia August 28-September 2. Second Battle of Bull Run August 30. Maryland Campaign September 6–22. Battle of Antietam September 16–17. Shepherdstown September 19. At Sharpsburg, Md., until October 30. Movement to Falmouth, Va., October 30-November 19. Battle of Fredericksburg December 12–15. Expedition to Richard's and Ellis' Fords December 29–30. "Mud March" January 20–24, 1863. At Falmouth until April. Chancellorsville Campaign April 27-May 6. Battle of Chancellorsville May 1–5. Participated in the Gettysburg Campaign June 11-July 24, 1863. Battle of Gettysburg July 1–3. Bristoe Campaign October 9–22. Advance to line of the Rappahannock November 7–8. Mine Run Campaign November 26-December 2. Campaign from the Rapidan to the James May 3-June 2. Battle of the Wilderness May 5–7. Spotsylvania May 8–12. Spotsylvania Court House May 12–21. North Anna River May 23–26. On line of the Pamunkey May 26–28. Totopotomoy May 28–31. Casualties The regiment lost a total of 124 men during service; 3 officers and 61 enlisted men killed or mortally wounded, 1 officer and 59 enlisted men died of disease. Commanders Colonel Daniel Butterfield - commander of the three-month regiment Colonel Ezra L. Walrath - first commander of the two-year regiment Colonel George W. Snyder Colonel Henry A. Weeks - commanded the 12th New York battalion of three-year volunteers that joined the two-year regiment in the field, and commanded the two-year regiment as a result Colonel Benjamin A. Willis Major Henry W. Ryder - promoted from