HEADQUARTERS PATRICK'S BRIGADE,

Camp near Sharpsburg, Md., September 21, 1862.

CAPTAIN: In obedience to the call from division headquarters for a report of the operations of the brigade under my command on the 17th instant, I have the honor to report the following statement:

The brigade, composed of the Twentieth New York State Militia, Twenty-first, Twenty-third, and Thirty-fifth New York Volunteers, leaving its position with the main body of the army near Keedysville toward evening on the 16th, crossed the ford of the Antietam, and marched nearly parallel with the other columns, my brigade leading the division commanded by General Doubleday. Arrived within three-quarters of a mile of the road from Sharpsburg to Williamsport, the Pennsylvania Reserves, General Meade commanding, became engaged on our left and in the woods with the enemy, whom they drove about half a mile. Meantime, and just as darkness was coming on, I was directed by a staff officer of General Hooker to place my brigade in and hold an open wood, skirting the Sharpsburg road. Although taking no part in the action, several of my men were wounded by the enemy's fire before and while taking position in the wood. I was then directed to connect my pickets with those of General Meade on my left, but owing to the darkness it was some time before this could be accomplished.

At this time Lieutenant-Colonel Hofmann, of Doubleday's brigade, coming up with his command, was placed in the interval between the Reserves and my brigade. As Colonel Hofmann was directly exposed to the action of a battery in his front, he brought up in the night some guns, and placed them in position to meet the fire of the enemy. The whole command lay on arms during the night, and at daybreak next morning (17th) the enemy opened fire upon us with round-shot, shell, and canister, by which a few of our men were wounded. My brigade, having led the day before, was now ordered to follow and support Gibbon's brigade, which had remained over night at some distance on my left and rear.

Putting my brigade in motion, we marched across the open field and into the wood beyond, through the plowed field and orchard into a corn-field, where Gibbon's brigade lay, and where my own was placed in its support. We could not have remained here more than from five to seven minutes, when I received an order from General Doubleday to march my brigade rapidly across the road, and hold the woods at a little distance on the right of the road. This movement was rapidly executed, but while in progress an order from General Doubleday directed me to send a regiment to protect a battery in the corn-field near the straw-stack. The Twentieth Regiment New York State Militia, Lieutenant-Colonel Gates commanding, was instantly countermarched, and reported to General Gibbon, at Battery B, Fourth U. S. Artillery, where it remained until the battery was withdrawn, some hours after. The Seventh Wisconsin Regiment crossed the road at the same time with my brigade, and took position in the wood parallel with and in advance of the lines, on the other side of the road beyond the battery, where it joined the Nineteenth Indiana, which had preceded it by only a very few minutes.

Scarcely had my three regiments reached the woods when a body of the enemy was discovered filing off to our right and rear into a corn-field, where a small battery had already been placed, and, on reporting the fact to General Hooker, he directed that one of my regiments should be detached to watch and check the movement. Colonel Hofmann, with the Twenty-third Regiment, was dispatched to the right to head off the enemy in that direction, and the Twenty-first and Thirty-fifth moved forward into the wood, closing upon the two regiments of Gibbon's brigade, whose skirmishers were now at the brow of the little eminence above the low grounds, in front of which was a corn-field, from which came the enemy's fire.

The fire of the enemy up to this time was brisk, not heavy, but on reaching this point a most galling fire was poured in from the enemy, strongly posted behind the rocks on our left, and my two regiments, Twenty-first and Thirty-fifth, were thrown forward into the first line to meet it. The troops on the opposite side of the road and fields and along the edge of the woods were now being rapidly driven back, and to check this advantage of the enemy, as well as to protect Battery B, on my left, I threw my whole command, including the Seventh Wisconsin and Nineteenth Indiana, across the open space and under the rocky ledge, perpendicular to my former position and parallel to the road, when I was joined at double-quick by the Twenty-third, now relieved on the right by General Meade. We remained but a few minutes here before we had checked the enemy's advance sufficiently to push our lines up to the road, which we held firmly for some time, the Thirty-fifth Regiment capturing the colors of the rebel regiment advancing on our battery. . . .

. . . From this wood, after about threequarters of an hour, we retired to a position near to and supporting the batteries in the open field, where we were joined by Lieutenant-Colonel Gates, of the Twentieth, who had been serving with Campbell's battery and had captured the battle-flag of one of the rebel regiments. . . .

M. R. PATRICK,
Brigadier-General, Commanding.

OR V 19, Pt. 1, Ser. 27, p. 243/5