80th New York Infantry (20th Militia)

At Antietam on the morning of 17 September 1862 ...

... two sections of Battery B, Captain Campbell, were stationed between some stacks of straw and a barn [David Miller's], and the enemy s sharpshooters had crept up until they had gotten within range, and were picking off the horses and gunners. ... the "Twentieth" was detached and sent back to support Captain Campbell s battery, against which the enemy were seen to be advancing in considerable force. Returning at "double-quick" the right wing formed near the guns, while the left wing under Major Hardenburgh, advanced down the field, along the road side, behind the fences of which and in the cornfield on the opposite side the enemy were posted, and from whence they commanded the position of the battery; they had also taken possession of a hollow piece of ground just in front of the guns. Major Hardenburgh pushed forward, under a hot fire, driving the enemy from their cover, and clearing the ground and the edge of the cornfield on our left. The Sixth Wisconsin, which had advanced into the cornfield on Major Hardenburgh s left, was very roughly handled by the enemy in its front, and was thrown into disorder and forced to retire. Its color-bearer was shot down, and its colors left on the field. Major Hardenburgh covered the retreat of the Wisconsin regiment, and brought off its colors. He also captured and brought off a Confederate battle-flag, the bearer of it having been shot down by private Isaac Thomas of G company. The enemy were soon re-enforced; and, advancing upon Major Hardenburgh in overwhelming numbers, he was obliged to fall back, which he did deliberately, delivering his fire as rapidly as the men could load, while the battery and the right wing opened upon the advancing rebels, who seemed resolved to take the guns.

Hardenburgh joined the right wing, and the regiment poured a steady fire into the brave fellows, whose courage and resolution won our admiration, although displayed in so bad a cause. For a time they drove the gunners from their pieces, but they could not endure the withering fire of the regiment at close quarters, and they fell back under cover of the ridge, a few hundred yards in front of our position. But it was only for a brief breathing spell the battery was the nearest one to their line of battle, and had done splendid execution, and Jackson had ordered its capture. Re-enforced and reorganized, on they came again, rising the knoll and coming over the open field in splendid order; delivering their fire as they advanced, and receiving that of their adversaries without wavering, they gave one of the finest exhibitions of manhood and pluck ever seen on any battle-field. Captain Campbell had double-shotted his guns in fact, filled them to the muzzle with grape and canister, and reserving his fire until the Confederate line was within fifty feet of him, he gave the word to fire! and the guns were discharged almost in the faces of the foe. The havoc was frightful. Their ranks were torn to pieces. The "Twentieth" on the instant poured in a deadly volley, and then sprang forward with the bayonet. The remnant of the rebel line broke and fled, leaving the ground covered with their dead and wounded. No further attempt was made against this position; and this practically ended the "Twentieth's" participation in the fight, although it remained in line of battle and under fire most of the day. 1

Detail Map #1: Hookers First Corps Sweeps Down the Hagerstown Pike (5-7 am)
Detail Map #2: Hood's Division Retakes Miller's Cornfield (7-8 am)
Detail Map #3: Mansfield's Twelfth Corps Attacks into Miller's Cornfield (7-9 am)
Detail Map #5: Sedgwick is Flanked in the West Woods (9-10am)

Tablet #1: First Army Corps - 16 Sep, 2 PM to 16 Sep, 6 PM
Tablet #13: Doubleday's Division, First Army Corps - 16 Sep, 2 PM to 16 Sep, 8 PM
Tablet #120: Army of the Potomac - 17 Sep, 5 AM to 17 Sep, 12 PM
Tablet #2: Doubleday's Division, First Army Corps - 17 Sep, 5 AM to 17 Sep, 9 AM
Tablet #3: Doubleday's Division, First Army Corps - 17 Sep, 5 AM to 17 Sep, 9 AM
Tablet #5: Patrick's Brigade, Doubleday's Division - 17 Sep, 5 AM to 17 Sep, 9 AM
Tablet #110: Patrick's Brigade, Doubleday's Division - 17 Sep, 5 AM to 17 Sep, 9 AM

See an excellent website on this unit. The unit should properly be called the 20th New York State Militia (NYSM).

See also an interesting study of controversy over the fate of the flag of the 6th Wisconsin at Antietam involving the 20th (from Blue and Gray Magazine, Winter 2005).