Beautiful and clear the morning broke over the Maryland hills on the fateful 17th of September, 1862. The sunlight had not yet touched the crowned hilltops when artillery fire announced the opening of the battle. The contest was opened by Hooker with about 8,000 men. He made a vigorous attack on the Confederate left, commanded by Jackson, and was supported by Doubleday on the right, and Meade on the left. He had not gone far before the glint of the rising sun disclosed the bayonet points of a large Confederate force standing in a cornfield in his immediate front. This was a part of Jackson's corps, who had arrived during the morning of the 16th from the capture of Harper's Ferry, and had been posted in this position to surprise Hooker in his advance. The outcome was a terrible surprise to the Confederates. Hooker's batteries hurried into action and opened with canister on the cornfield. Hooker's object was to push the Confederates back through a line of woods and seize the Hagerstown road and the woods beyond in the vicinity of the Dunker church. Around this church on this fateful day the demon of war reigned supreme, and near this church stood the fine mansion of a Mr. Mumma, which was fired by a retreating column of Confederate troops and burned throughout the entire engagement. The Federal batteries on the east side of the Antietam poured an enfilading fire on Jackson that galled him very much. The Confederates stood bravely against this fire and made a determined resistance. Back, and still further back, were Jackson's men driven across the field, every stalk of corn in which was cut down by the shot and shell as closely as a knife could have done it. On the ground the fallen lay in rows, precisely as they had stood in the ranks. The Confederates were driven from the cornfield into a patch of woods. Hooker now advanced his center under Meade to seize the Hagerstown road and the woods beyond. They were met by a murderous fire from Jackson, who had just been reënforced by Hood's refreshed troops, who fell heavily upon Meade in the cornfield. Hooker called upon Doubleday for aid, and a brigade was forwarded at double-quick across the cornfield in the face of a terrible storm of shot and shell. The Federals were further reënforced by Mansfield's corps, and while his divisions were deploying this veteran commander was mortally wounded. General Williams succeeded to the command of his corps, who pushed on across the open fields and seized a part of the woods on the Hagerstown road. At the same time Greene's division took position to the left of the Dunker church. This was on high ground and was the key to the Confederate left wing. But Greene's troops were exposed to a galling fire from the division of D. H. Hill and he called for reënforcements. General Sumner sent Sedgwick's division across the creek to reënforce Greene. His troops advanced straight towards the conflict. They found General Hooker severely wounded in the foot, which became so painful that he was carried off the field and left his troops in the command of Sumner. A sharp artillery fire was turned on Sedgwick before he reached the woods, west of the Hagerstown Pike, but once in the shelter of the thick trees he passed in safety to the western edge. Here the division found itself in an ambush.

The Confederates had been heavily reënforced by several brigades under Walker and McLaws, having just arrived from Harper's Ferry, and had not only blocked the front but had worked around to the rear of Sedgwick, who was wounded in the awful slaughter that followed, but he and Sumner finally extricated their men after severe loss. The Federals were now reënforced by Franklin's fresh troops and were able to hold the cornfield and part of the woods over which the conflict had raged till the ground was saturated with blood.

Sedgwick was twice wounded and carried from the field. The command of his division involved on General Howard.

It was now about noon and the battle had been raging since early in the morning. Another deadly conflict was in progress near the center. Sumner's corps had crossed the stream and made a desperate assault on the Confederates under D. H. Hill, stationed to the south of where the battle had previously raged and along a sunken road, since known as "Bloody Lane." The fighting here was of a most desperate character and continued nearly four hours. The Federal advance was led by Generals French and Richardson, who captured a few flags and several prisoners, but failed to carry the heights along which the Confederates were posted. Richardson was mortally wounded while leading a charge and was succeeded by General Hancock, but his men finally captured Bloody Lane with the 300 living men who remained to defend it.

The final Federal charge was made at this point by Colonel Barlow, who displayed the utmost bravery, where he won a brigadier-generalship. He was later wounded and carried off the field. The Confederates had fought desperately to hold their position at Bloody Lane, and when it was captured it was filled with dead bodies. It was now after one o'clock and the firing ceased for the day on the Union right and center.

General Burnside was in command of the Federal left wing and had remained inactive for some hours after the battle had begun at the other end of the line, having finally received orders from McClellan to cross the stone bridge, since known as Burnside's Bridge, and drive the Confederates out of their strong position. The Confederates at this bridge were commanded by General Toombs, who had orders from General Lee to hold the bridge at all hazards. They were behind strong breastworks and rifle pits, which commanded the bridge with both a direct and enfilading fire. General Robert Toombs had been a former United States senator and a member of Jefferson Davis' cabinet. Perhaps the most notable event of his life was the holding of the Burnside Bridge at Antietam for three hours against the fearful onslaughts of the Federals. Burnside's chief officer at this time was General Jacob D. Cox, afterwards governor of Ohio, who succeeded General Reno, killed at South Mountain or Boonsborough Gap. On General Cox fell the task of capturing the stone bridge.

The Confederates had been weakened at this point by the sending of Walker to the support of Jackson, where, as we have noticed, he took part in the deadly assault upon Sedgwick's division.

Toombs, with his small force, had a hard task of defending the bridge, notwithstanding his advantage of position. McClellan sent several urgent orders to General Burnside to cross the bridge at all hazards. Burnside forwarded these to Cox and in the fear that the latter would not be able to carry the bridge by a direct front attack, he sent General Rodman with a division to cross the creek at a ford below. This was accomplished after much difficulty. One assault after another was made upon the bridge in rapid succession, which was at length carried at the cost of 500 men. Burnside charged up the hill and drove the Confederates almost to Sharpsburg. The fighting along the Sharpsburg road might have resulted in the Confederates' disaster and the capture of General Lee's headquarters had it not been for the timely arrival of A. P. Hill's division, which emerged out of a cloud of dust on the Harper's Ferry road and came upon the field at double quick, and, under a heavy fire of artillery, charged upon Burnside's columns and after severe fighting, in which General Rodman was mortally wounded, drove the Federals back almost to the bridge. The pursuit was checked by the Federal artillery on the eastern side of the stream. Darkness closed the conflict.

Lee had counted on the arrival of A. P. Hill in time to help hold the Federals in check at the bridge, but he was late and came up just in time to save the army from disastrous defeat.

With the gloom of that night ended the conflict known as Antietam.