Report of Lieutenant Colonel Samuel M. Jackson, Eleventh Pennsylvania Reserves of operations September 14-17.

HDQRS. 11TH Regiment, PENNSYLVANIA RESERVE VOL. CORPS,
Camp near Sharpsburg, Md., October 2, 1862.

SIR: I have the honor herewith to report the part taken by the Eleventh Regiment, Pennsylvania Reserve Volunteers Corps, in the battles of South Mountain and Antietam, September 14, 16, and 17, 1862:

On the afternoon of Sunday, September 14, my regiment was ordered by Colonel Gallagher, then commanding Third Brigade, to support a section of Captain Cooper's battery, which had been placed in position to bear upon a battery of the enemy that had been shelling our brigade furiously as we approached the base of the mountain. We had been in position but a few minutes when I received orders to advance my regiment to the front in closed columns of division until we emerged from the corn-field, when we were to deploy in line of battle on the left of the Ninth Regiment, Pennsylvania Reserve Volunteer Corps. I immediately complied with this order, and on reaching the open field moved my regiment forward in line of battle with the balance of the brigade. We were here exposed to a shower of shell from the enemy's batteries, which, fortunately, took no effect on my command. I ordered my men to press forward rapidly to a ravine at the foot of the mountain, but on reaching this we received a deadly volley from the enemy's infantry, who were strongly posted in the rocks on the mountain side and but a short distance from our lines. This single volley brought down more than the half of my commissioned officers present, but the men continued to press forward with a seeming determination to win, and soon succeeded in forcing the enemy from their strong and well-selected position, when they continued to drive them steadily before them to the mountain top. I was here apprised of the shortness of our ammunition, and on reporting the same to lieutenant Bemus, acting assistant adjutant-general, Third Brigade, I was told we would soon be relieved, when we could have our empty boxes replenished. Soon after this General Duryea's brigade advanced and covered a portion of my front. Darkness having stopped the farther pursuit of the enemy for the night, I ordered a portion of my men to see to the carrying of our wounded, as up to this time they had been left untouched on the field. Our casualties in this day's engagement were as follows: Killed, Captain E. R. Brady, Lieutenant W. F. Jackson, and 10 enlisted men; wounded, Colonel Thomas F. Gallagher, Captain Nat. Nesbitt (since dead), Captain Everard Bierer, Lieutenant and Quartermaster H. A. Torrence, Lieutenant James S. Kennedy, and 25 enlisted men. On Tuesday evening, September 16, after having crossed Antietam Creek, my regiment, with the balance of the Third Brigade, was ordered to take a position in line of battle in a strip of woods and on the right of Captain Cooper's battery, which we succeeded in doing under a terrific shower of shell from the enemy's batteries in our front and on our right, with the loss of one man wounded of my command. I was then ordered by Lieutenant-Colonel Anderson, commanding Third Brigade, to hold our position here at any cost, and to cover our entire front by a strong line of skirmishers, which later order I complied with by posting a line of skirmishers along the outer edge of the woods and near to the enemy's lines. At early dawn Wednesday, September 17, my regiment was ordered forward, with the balance of the Third Brigade, to support a portion of General King's forces, which had advanced and drove the enemy through a corn-field in our front. We were ordered by General Meade to halt our command