5th Pennsylvania Reserves

[South Mountain] ... suddenly the regiments of the First Brigade [3rd Division, 1st Corps] arrived at a cornfield,'full of rebels,' protected by a stone wall at the foot of the abrupt mountain side; the Bucktails received a terrific volley of musketry, which brought them to a halt; General Seymour, who was on the ground with his men, seeing that this was the critical moment, called out to Colonel Roberts, commanding the First Regiment, to charge up the mountain, and at the same instant, turning to Colonel Fisher, of the Fifth Regiment, whose men were coming up in well dressed lines, he exclaimed: 'Colonel, put your regiment into that cornfield and hurt somebody. ''I will, General, and'll catch one alive for you,' was the cool reply of Colonel Fisher. The Second regiment, commanded by Captain Byrnes, and the Sixth, Colonel Sinclair, were ordered forward at the same time. The men of the Fifth leaped the stone wall, immediately captured eleven prisoners, and sent them back to the General.

The regiment steadily ascended the rugged side of the mountain under a heavy fire of artillery and musketry, and after a severe struggle, lasting five hours, carried the heights with the triumphant division and planted its standard upon the summit. It entered the engagement with three hundred and fifty-seven men. Its loss was one killed and nineteen wounded.

On the night of the 14th, the men slept on their arms, on the rugged mountain crest. At early dawn of the 15th, finding that the enemy had fled, the regiment moved down the mountain, and passing Boonsboro bivouacked for the night at Keedysville.

On the 16th, it crossed Antietam Creek, and moving to the right, engaged the enemy at four P. M., and was engaged at intervals during the night. The battle was renewed at daylight on the following morning, and raged with unabated fury on that part of the line where the Reserves were posted during the early part of the day, the Fifth not being relieved until one P. M.

... and on the 19th, the Fifth marched to the river, near Sharpsburg, where it encamped. The loss of the Fifth in this battle was two killed and eight wounded.

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)

Tablet #1: First Army Corps - 16 Sep, 2 PM to 16 Sep, 6 PM
Tablet #15: Meade'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 #17: Seymour's Brigade, Meade's Division - 17 Sep, 6 AM to 17 Sep, 8 AM
Tablet #11: Meade's Division, First Army Corps - 17 Sep, 6 AM to 17 Sep, 9 AM

The battle narrative above from Bates.1