Numbers 36. Report of Colonel Thomas F. McCoy, One hundred and seventh Pennsylvania Infantry, First Brigade, of operations August 17-31, including engagement at Thoroughfare Gap and battle of Bull Run.

HDQRS. ONE HUNDRED AND SEVENTH Regiment PA. VOLS.,
Camp near Mercerville, Md., October 8, 1862.

GENERAL: For your information I would respectfully present the following report of the operations of the One hundred and seventh Regiment Pennsylvania Volunteers while under my command in the Army of Virginia, terminating on the 31st day of August, 1862:

Having advanced to the line of the Rapidan August 17, 1862, near to the overwhelming columns of the enemy, the counter-movement in the direction of the Rappahannock began on the following day, August 18, 1862. After undergoing most tedious and fatiguing marches the north bank of that river at the railroad station was reached on the night of August 19. On the following day (20th) the enemy appeared in front from the direction of Culpeper, supposed to be in great force. During this and the two succeeding days and nights and the next day (the 23rd) until 10 o'clock in the forenoon we were under arms and in line of battle, supporting the batteries in our immediate front, and although much exposed during the various artillery engagements, the casualties were few. Continuing the march toward Warrenton and passing three days near the lines of the enemy in the vicinity of the White Sulphur Springs and village of Waterloo, during which time almost constant artillery skirmishing was going on, your brigade, with the division (Ricketts'), directed its march on the night of the 27th for Thoroughfare Gap, via Hay Market, where it arrived in the afternoon of the 28th and was almost immediately advanced against the enemy, said to be Longstreet's corps, on its way to the support of Jackson, then understood to be engaged with a part of our army near Manassas.

Immediately on coming up to your position on the field your order was given to advance with the One hundred and seventh to the support of Captain Thompson's battery on the right of the line and to protect the line of railroad in that quarter of the field. During the progress of the action this battery was removed to the left of the road leading into the Gap, when your order was received to rejoin the brigade, then near that point. The action had become during these movements very spirited and the enemy's skirmishers were being driven into the Gap and up the mountain on both sides. Meeting you on the road near one of the advanced batteries your ordered me to advance the regiment to the summit of the ridge on the right. This movement was promptly executed and partly under your own observation and the different members of your staff, Captain Duryea and Lieutenants Neill, Starks, and Kenney, through whom I received frequent communications from you during the afternoon. Being on the ridge, we were soon after joined by the Ninety-seventh, One hundred and fourth, and One hundred and fifth New York Regiments, which, with the One hundred and seventh Pennsylvania Volunteers, compose your brigade, and remained in support of Captain Matthews' Pennsylvania battery until the enemy were driven, as I believe, far into the Gap, when the division, having performed the duty assigned it-darkness approaching, and being in danger of large forces of the enemy flanking our small force-(being Ricketts' division only) withdrew, via Hay Market, in the direction of