The 3rd Delaware Volunteer Infantry Regiment lost 7 officers and 46 enlisted men killed or mortally wounded and 2 officers and 80 enlisted men to disease during the Civil War. It is honored by a monument at Antietam.

December 30, 1861 – May 15, 1862 Organized at Camden
May Ordered to Washington, D.C. and attched to Slough’s Brigade, Defenses of Washington
May 28-30 Defense of Harper’s Ferry attached to Slough’s 2nd Brigade, Sigel’s Division, Dept. of the Shenandoah
June – July Operations in the Shenandoah Valley attached to 2nd Brigade, 2nd Division, 2nd Army Corps, Army of Virginia
August Attached to 3rd Brigade, 2nd Division, 2nd Army Corps, Army of Virginia
August 9 Battle of Cedar Mountain
August 16-
September 2
Pope’s Campaign in Northern Virginia
August 23-24 Sulphur Springs
August 29 Groveton
August 30 Bull Run and Sulphur Springs
September 1 Chantilly
September 6-22 Maryland Campaign. Attached to 3rd Brigade, 2nd Division, 12th Army Corps, Army of the Potomac
September 14 Battle of South Mountain
September 16-17
Battle of Antietam

The regiment was commanded by Colonel Arthur Maginnis until he was wounded. Captain William J. McKaig then took over.

From the monument on the Antietam battlefield:

This regiment, worn down from active service in the second Manassas Campaign, went into action Sept. 17, 1862 with only five officers and 120 men. It started out on the right of the Union line in front of the West Woods. After heavy action along the Hagerstown Pike, it helped repulse Confederate counter attack following rout of Sedgewick’s Division. Final position of the regiment, 65 yards North of this point.

Officers  Men
Killed                1         5
Wounded         2         9
Total  17 of 125 engaged

October Attached to Defenses of Baltimore, Md., 8th Army Corps, Middle Dept. Duty at Frederick, Maryland., Relay House, Md., and Elysville, Md., guarding the Baltimore & Ohio Railroad
January Attached to 3rd Separate Brigade, 8th Army Corps
May Ordered to Join Army of the Potomac in the field; attached to 2nd Brigade, 4th Division, 5th Army Corps
May 29-June 15 Rapidan Campaign
May 29-31 Totopotomoy
June 1-12
Battle of Cold Harbor
June 16-18 First Assault on Petersburg
June 16 Siege of Petersburg
July 30 Mine Explosion, Petersburg (Reserve)
August 18-21 Weldon R. R. Attached to 3rd Brigade, 2nd Division, 5th Army Corps
September 29-
October 2
Poplar Springs Church
October 27-28 Boydton Plank Road, Hatcher’s Run
December 7-12 Warren’s Raid on Weldon R. R.
February 5-7 Dabney’s Mills, Hatcher’s Run
March 28-April 9 Appomattox Campaign
March 29 Lewis Farm, near Gravelly Run
March 30-31 Boydton and White Oak Roads
April 1
Battle of Five Forks
April 2 Fall of Petersburg
April 3-9 Pursuit of Lee
April 9
Appomattox Court House

Surrender of Lee and his army.

May 1-12 March to Washington, D.C.
May 23 Grand review
June 3 Mustered out