The 21st Connecticut Volunteer Infantry Regiment lost 5 officers and 55 enlisted men killed or mortally wounded and 1 officer and 114 enlisted men to disease during the Civil War.

September 5 Organized at Norwich
September 11 Left State for Washington, D.C.
Duty at Arlington Heights, Va., Defenses of Washington, D.C. attached to 2nd Brigade, 3rd Division, 9th Army Corps, Army of the Potomac
November 7-19 March to Falmouth, Va.
December 12-15
Battle of Fredericksburg
January Assigned to 3rd Brigade, 3rd Division, 9th Army Corps
January 20-24 Burnside’s 2nd Campaign, “Mud March”
February 6-9 Moved to Newport News, Va.
March 13 To Suffolk, Va.
April 12-May 4 Siege of Suffolk, assigned to 3rd Brigade, 2nd Division, 7th Army Corps, Dept. of Virginia
May 3 Chuckatuck and Reed’s Ferry, Nansemond River
May 4 Siege of Suffolk raised
June 9-16 Reconnaissance to Chickahominy
June 16 Moved to Portsmouth, Va. and assigned to 3rd Brigade, Getty’s Division, Portsmouth, Va., Dept. of Virginia and North Carolina for provost and guard duty at Portsmouth and Norfolk
October Assigned to Heckman’s Command, Newport News, Va., Dept. Virginia and North Carolina
November 10 Moved to Newport News
February Assigned to Defenses of New Berne, N. C., Dept. Virginia and North Carolina
January 24-25 Expedition up James River to Fort Powhatan
February 1 Smithfield
February 3 Moved to Morehead City, N. C.
February 12 To New Berne and duty there, at Plymouth and at Washington, N. C.
March Assigned to Sub-District of the Pamlico, N. C., Dept. Virginia and North Carolina
April 5 Near Blount’s Creek
April 28 Moved to Portsmouth, Va.
May 10-28 Butler’s operations on South Side of the James River and against Petersburg and Richmond. Assigned to 3rd Brigade, 1st Division, 18th Army Corps, Dept. of Virginia and North Carolina.
May 10 Swift Creek, or Arrow field Church
May 12-16 Operations against Fort Darling
May 14-16 Battle of Drewry’s Bluff
May 17-27 At Bermuda Hundred
May 27-31 Moved to White House, then to Cold Harbor
June 1-12
Battles about Cold Harbor
June 15-18 First Assault on Petersburg
June 18 Siege operations against Petersburg and Richmond begin
June 24-28 Hare’s Hill
August 25-
September 27
In trenches at Bermuda Hundred
September 28-30 Chaffin’s Farm, New Market Heights
October 27-28 Fair Oaks
December Assigned to 3rd Brigade, 3rd Division, 24th Army Corps, Dept. of Virginia
March Duty in trenches before Richmond
March 5-8 Expedition to Fredericksburg
March 11-13 Expedition up the Potomac River
March 13-18 Moved to White House
March 24-26 To Signal Hill, before Richmond
April 3 Occupation of Richmond
April 28 Moved to Columbia
June 16 Mustered out