Organized at Washington, D. C., from 4th Conn. Infantry, January 2, 1862. Attached to Military District of Washington to April, 1862. Siege artillery, Army Potomac, to May, 1862. 3rd Brigade, 2nd Division, 5th Army Corps, Army Potomac, to July, 1862. Siege artillery, Army Potomac, to August, 1862. Artillery defences Alexandria Military District of Washington, to February, 1863. Artillery defences of Alexandria, 22nd Army Corps, to April, 1863. 2nd Brigade, DeRussy's Division, defences south of the Potomac, 22nd Army Corps, to May, 1863. 3rd Brigade, DeRussy's Dlvision, 22nd Corps, to December, 1863. 2nd Brigade, DeRussy's Division, 22nd Army Corps, to March, 1864. 4th Brigade, DeRussy's Division, 22nd Army Corps, to May, 1864. (Cos. "B" and "M" attached to Artillery Reserve, Army Potomac, October, 1862, to January, 1864.) Point of Rocks, Va., Dept., of Virginia and North Carolina to June, 1864. Siege artillery, Dept. of Virginia and North Carolina in the field, and siege artillery, Army Potomac, to May, 1865. Siege artillery, Dept. of Virginia, to July, 1865. 4th Brigade, DeRussy's Division, 22nd Army Corps, Dept. of Washington, to August, 1865. 3rd Brigade, Dept. of Washington, to September, 1865.

SERVICE:
Duty at Fort Richardson, defences of Washington, D. C., till April, 1862. Ordered to the Peninsula, Va., in charge of siege train Army Potomac, April 2. Siege of Yorktown April 12-May 4. Battle of Hanover C. H. May 27. Operations about Hanover May 27-29. Seven days before Richmond June 25-July 1. Gaines' Mill June 27. Malvern Hill July 1. At Harrison's Landing till August 15. Moved to Alexandria, Va., August 16-27. Duty in the defences of Washington, D. C., till May, 1864, as garrison at Fort Richardson. Cos. "B" and "M" detached with Army Potomac, participating in battle of Fredericksburg, Va., Dec. 12-15. Chancellorsville Campaign April 27-May 6. Battle of Chancellorsville May 1-5. Stafford Heights June 12. Battle of Gettysburg, Pa., July 1-3. Bristoe Campaign October 9-22. Advance to line of the Rappahannock November 7-8. Brandy Station November 8. Mine Run Campaign November 26-December 2. Rejoined regiment in defences of Washington January, 1864. Regiment ordered to Bermuda Hundred, Va., May 13, 1864. Engaged in fatigue duty and as garrison for batteries and forts on the Bermuda front and lines before Petersburg during siege operations against Petersburg and Richmond, May, 1864, to April, 1865. Occupy Fort Converse, Redoubt Dutton, Batteries Spofford, Anderson, Pruyn and Perry on the Bermuda front, and Forts Rice, Morton, Sedgewick and McGilvrey, and Batteries 1, 2, 3, 4, 5, 9, 10, 11, 12, 14, 15, 17, 18, 20, Burpee, Drake and Sawyer, on the Petersburg front, and at Dutch Gap, north of the James River. Assaults on Fort Dutton June 2 and 21, 1864 (Co. "L"). Attacks on the lines May 18, 19, 20, 21, 25, 27, 30, 31, June 1, 2, 5, 9, 18, 20 and 23. Mine explosion July 30, August 25, November 17, 18 and 28, 1864. Repulse of rebel fleet at Fort Brady on James River January 23-24, 1865. Expedition to Fort Fisher, N. C., January 3-15, 1865 (Cos. "B," "G," "L"). Capture of Fort Fisher January 15 (Cos. "B," "G," "L"). Assaults on and fall of Petersburg, Va., April 2, 1865. Duty in the Dept. of Va. till July 11. Moved to Washington, D.C. and duty in the defences of that city till September. Mustered out September 25, 1865.

Regiment lost during service 2 Officers and 49 Enlisted men killed and mortally wounded and 4 Officers and 172 Enlisted men by disease. Total 227.