Rebellion Record: a Diary of American Events: Documents and Narratives, Volume 5.
Frank Moore, Ed.

Under the base of these hills runs the deep stream called Antietam Creek, fordable only at distant points. Three bridges cross it, one on the Hagerstown road, one on the Sharpsburgh pike, one to the left in a deep recess of steeply falling hills. Hooker passed the first to reach the ford by which he crossed, and it was held by Pleasanton with a reserve of cavalry during the battle. The second was close under the rebel centre, and no way important to yesterday's fight. At the third, Burnside attacked and finally crossed. Between the first and third lay most of the battle-lines. They stretched four miles from right to left.

Unaided attack in front was impossible. McClellan's forces lay behind low, disconnected ridges in front of the rebel summits, all or nearly all unwooded. They gave some cover for artillery, and guns were therefore massed on the centre. The enemy had the Shepherdstown road and the Hagerstown and Williamsport road both open to him in rear for retreat. Along one or the other, if beaten, he must fly. This among other reasons determined, perhaps, the plan of battle which McClellan finally resolved on.

The plan was generally as follows: Hooker was to cross on the right, establish himself on the enemy's left if possible, flanking his position, and to open the fight. Sumner, Franklin, and Mansfield were to send their forces also to the right, cooperating with and sustaining Hooker's attack while advancing also nearer the centre. The heavy work in the centre was left mostly to the batteries, Porter massing his infantry supports in the hollows. On the left, Burnside was to carry the bridge already referred to, advancing then by a road which enters the pike at Sharpsburgh, turning at once the rebel flank and destroying his line of retreat. Porter and Sykes were held in reserve. It is obvious that the complete success of a plan contemplating widely divergent movements of separate corps, must largely depend on accurate timing — that the attacks should be simultaneous and not successive.

Hooker moved Tuesday afternoon at four, crossing the creek at a ford above the bridge and well to the right, without opposition. Fronting southwest, his line advanced not quite on the rebel flank but overlapping and threatening it. Turning off from the road after passing the stream, he sent forward cavalry skirmishers straight into the woods and over the fields beyond. Rebel pickets withdrew slowly before them, firing scattering and harmless shots. Turning again to the left, the cavalry went down on the rebel flank, coming suddenly close to a battery which met them with unexpected grape and canister. It being the nature of cavalry to retire before batteries, this company loyally followed the law of its being, and came swiftly back without pursuit.

Artillery was sent to the front, infantry was rapidly deployed, and skirmishers went out in front and on either flank. The corps moved forward compactly, Hooker as usual reconnoitring in person. They came at last to an open grass-sown field inclosed on two sides with woods, protected on the right by a hill, and entered through a corn-field in the rear. Skirmishers penetrating these woods were instantly met by rebel shots, but held their ground, and as soon as supported, advanced and cleared the timber. Beyond, on the left and in front, volleys of musketry opened heavily, and a battle seemed to have begun a little sooner than it was expected.

General Hooker formed his lines with precision and without hesitation. Ricketts's division went into the woods on the left in force. Meade with the Pennsylvania reserves formed in the centre. Doubleday was sent out on the right, planting his guns on the hill, and opening at once on a rebel battery that began to enfilade the central line. It was already dark, and the rebel position could only be discovered by the flashes of their guns. They pushed forward boldly on the right after losing ground on the other flank, but made no attempt to regain their hold on the woods. The fight flashed, and glimmered, and faded, and finally went out in the dark.

Hooker had found out what he wanted to know. When the firing ceased, the hostile lines lay close to each other — their pickets so near that six rebels were captured during the night. It was inevitable that the fight should recommence at daylight. Neither side had suffered considerable loss; it was a skirmish, not a battle. “We are through for to-night, gentlemen,” remarked the General, “but to-morrow we fight the battle that will decide the fate of the republic.”

Not long after the firing ceased, it sprang up again on the left. General Hooker, who had taken his headquarters in a barn which had been nearly the focus of the rebel artillery, was out at once. First came rapid and unusually frequent picket-shots, then several heavy volleys. The General listened a moment and smiled grimly. “We have no troops there. The rebels are shooting each other. It is Fair Oaks over again.” So every body lay down again, but all the night through there were frequent alarms.

McClellan had been informed of the night's work, and of the certainties awaiting the dawn. Sumner was ordered to move his corps at once, and was expected to be on the ground at daylight. From the extent of the rebel lines developed in the evening, it was plain that they had gathered their whole army behind the heights and were waiting for the shock.

The battle began with the dawn. Morning found both armies just as they had slept, almost close enough to look into each other's eyes. The left of Meade's reserves and the right of Ricketts's line became engaged at nearly the same moment, one with artillery, the other with infantry. A battery was almost immediately pushed forward beyond the central woods, over a ploughed field near the top of the slope where the corn-field began. On this open field, in the corn beyond, and in the woods which stretched forward into the broad fields like a promontory into the ocean,