Organized at Concord, N. H., and mustered in October 22, 1861. Left State for Washington, D.C., October 29, 1861. Attached to Howard's Brigade, Sumner's Division, Army of the Potomac, to March, 1862. 1st Brigade, 1st Division, 2nd Army Corps, Army of the Potomac, to July, 1863. Concord, N.H., Dept. of the East, to November, 1863. Marston's Command, Point Lookout, Md., to May, 1864. 1st Brigade, 1st Division, 2nd Army Corps, Army of the Potomac, to June, 1865.

SERVICE.--Camp at Bladensburg, Defenses of Washington, D.C., until November 27, 1861. Expedition to Lower Maryland November 3-11. At Camp California, near Alexandria, Va., until March 10, 1862. Scout to Burke's Station January 17, 1862 (Co. "A"). Advance on Manassas, Va., March 10-15. Reconnaissance to Gainesville March 20, and to Rappahannock Station March 28-29. Warrenton Junction March 28. Moved to the Virginia Peninsula April 4. Siege of Yorktown, Va., April 5-May 4. Temporarily attached to Woodbury's Engineer Brigade. Construct Grapevine Bridge over Chickahominy May 28-30. Battle of Fair Oaks or Seven Pines May 31-June 1. Seven days before Richmond June 25-July 1. Orchard Station June 28. Peach Orchard, Allen's Farm and Savage Station June 29. White Oak Swamp and Glendale June 30. Malvern Hill July 1. At Harrison's Landing until August 16. Movement to Fortress Monroe, thence to Alexandria and to Centreville, Va., August 16-30. Cover Pope's retreat from Bull Run. Maryland Campaign September-October. Battle of South Mountain, Md., September 14 (Reserve). Antietam Creek, near Keadysville, September 15. Battle of Antietam, Md., September 16-17. Duty at Harper's Ferry, W. Va., September 21 to October 29. Reconnaissance to Charlestown October 16-17. Advance up Loudon Valley and movement to Falmouth, Va., October 29-November 17. Battle of Fredericksburg, Va., December 12-15. Burnside's Second Campaign, "Mud March," January 20-24, 1863. Duty at Falmouth until April. Chancellorsville Campaign April 27-May 6. Battle of Chancellorsville May 1-5. Reconnaissance to Rappahannock June 9. Gettysburg (Pa.) Campaign June 13-July 24. Battle of Gettysburg, Pa., July 1-3. Moved to Concord, N.H., July 26-August 3. Duty at Draft Rendezvous, Concord, N.H., until November. Moved to Point Lookout, Md., November 8-13, and duty there guarding prisoners until May 27, 1864. Moved to Cold Harbor, Va., May 27-June 1, and join Army of the Potomac. Battles about Cold Harbor June 1-12. Before Petersburg, Va., June 16-19. Siege of Petersburg June 16, 1864, to April 2, 1865. Jerusalem Plank Road June 22-23, 1865. Deep Bottom, north of James River, July 27-28. Mine Explosion, Petersburg, July 30 (Reserve). Demonstration north of James River August 13-20. Strawberry Plains August 14-18. Ream's Station August 25. Non-Veterans mustered out October 12, 1864. Reconnaissance to Hatcher's Run December 9-10. Dabney's Mills, Hatcher's Run, February 5-7, 1865. Watkins' House March 25. Appomattox Campaign March 28-April 9. On line of Hatcher's and Gravelly Runs March 29-30. Hatcher's Run or Boydton Road March 31. White Oak Road March 31. Sutherland Station April 2. Fall of Petersburg April 2. Saylor's Creek April 6. High Bridge and Farmville April 7. Appomattox Court House April 9. Surrender of Lee and his army. Moved to Washington, D.C., May 2-12 Grand Review May 23. Mustered out July 28, and discharged July 8, 1865. This Regiment sustained the greatest loss in battle of any Infantry or Cavalry Regiment in the Union Army. Total killed and wounded 1,051.