Battle of Antietam: Chronology and Aftermath

Posted on September 17, 2012
By Norman S. Stevens


17 September: THE BATTLE OF ANTIETAM (also known as Sharpsburg). It must be pointed out that the exact timing of events at Antietam are, to some extent only approximate. There were a vast number of watches on the field, with no common standard. Dawn, which is listed for 17 September at 0543, Major General Hooker’s Federal I Corps begins advance into the north woods with the divisions of Doubleday and Ricketts. The action against Jackson’s Confederate divisions commanded by Lawton and D. R. Jones commences at approximately 0615.

0700: Brigadier General John Hood’s Confederate Division counter-attacks Hooker’s forces; bitter fighting in the cornfield and in the east woods.

0720: Hood’s assault is repulsed; Federal XII Corps arrives on the field, deploying into the east woods by 0730.

0830: Major General Edwin Sumner brings Sedgwick’s division of Federal II Corps into the east woods; severe fighting continues.

0900: Federal I and XII Corps are fought out by now; French’s division of Federal II Corps arrives opposite the sunken road position, ultimately supported by Richardson’s Division of II Corps. Fighting dies out on the Confederate left by 1030.

0930: Federal II Corps divisions of French and Richardson begin to assault the sunken road position in the Confederate centre held by Major General D. H. Hill’s division. There is a great deal of bloody fighting until the position is finally taken by Federal forces at 1300, and then there is little subsequent activity at the Confederate centre. Meanwhile in the south, Major General Ambrose Burnside has received several orders, at least from 1000, to assault the bridge to his front. The stone bridge is finally taken by elements of Sturgis’s division of Federal IX Corps at 1300. The remainder of the Federal IX Corps is across Antietam Creek and advancing towards Sharpsburg by 1500.

Between 1545 and 1600, the Confederate division commanded by Major General Ambrose Powell Hill begins arriving on the field, after completing a seventeen mile march from the Harper’s Ferry area. Hill’s division counter-attacks Federal IX Corps, the action completed by 1630.

There is no further activity of significance anywhere on the field.

18 September: The Army of Northern Virginia begins recrossing the Potomac River into Virginia near Shepherdstown, West Virginia. The operation is completed on 19 September.


The Aftermath

The armies remained in position facing each other through the following day, but by the late afternoon of 18 September Lee was making preparations to withdraw the Army of Northern Virginia back to Virginia. Lee’s army completed the crossing of the Potomac River near Shepherdstown, West Virginia, on 19 September. A. P. Hill’s division was employed again at Boteler’s Ford near Shepherdstown on the morning of 20 September to secure the retreat of Lee’s reserve artillery. There was no really effective pursuit of Lee by the Army of the Potomac. The Maryland Campaign was over.

The battle of Antietam, Maryland, is correctly referred to as the single bloodiest day of the American Civil War. There were more casualties on 17 September 1862 than any recorded on any other field on any other day during the conflict. The Civil War statistician Thomas L. Livermore states that the Army of the Potomac suffered 2,108 dead, 9,549 wounded, 753 missing, for a total of 12,410 casualties. Livermore puts Confederate loses at 2,700 dead, 9,024 wounded, 2,000 missing, for a total of 13,724 casualties. This represents 26,134 casualties in a single day, more casualties than that suffered by the United States during the entire war with Mexico between 1846 and 1847. The United States Army had 1,721 combat deaths in Mexico, suffered 4,102 wounded, and sustained another 11,155 deaths from disease. There were 16,978 casualties in the entire conflict with Mexico, and at Buena Vista, perhaps one of the most severe battles of the Mexican War, the Americans had 665 total casualties. The contrast between the Mexican War experience and the single day of Antietam was a very sobering one for the participants. To the casualty totals of Antietam one could add 1,813 Federals and 2,685 Confederates who fell at South Mountain, and 533 Federal and an undetermined number of Confederate casualties for the action at Crampton’s Gap. The totals climb to 14,756 Federals and more than 16,409 Confederates, for a grand total in excess of 31,165 casualties for the Maryland Campaign. This was considered quite shocking, a general feeling reinforced by the circulation in civilian urban areas for the first time of photographs made on the battlefield of recent corpses. The horror of the war was brought home to many individuals, both civilian and military, by Antietam.

The engagements of Crampton’s Gap, South Mountain, and Antietam represented strategic victory for the North. McClellan had successfully defended Washington, halted Lee’s advance into Maryland, and had arguably inflicted a tactical defeat on the Army of Northern Virginia. Lee’s army was, in any case, retreating into Virginia. From a Northern perspective, the negative aspect was that a great opportunity to destroy Robert E. Lee’s Army of Northern Virginia completely had been missed. From a Southern viewpoint the Maryland operation contained some positive aspects, such as the reduction of Harper’s Ferry along with capture of substantial Federal war material, and the removal, at least temporarily, of the armies from Virginia. The negative items were somewhat more ominous for the Confederacy. No large numbers of Marylanders had eagerly clamoured to join Southern ranks, nor were there many individuals in Kentucky of similar inclination. In addition, Lee’s retreat from Sharpsburg, when coupled with Braxton Bragg’s retreat in Kentucky following the battle of Perryville (8 October 1862), ended any realistic chance of European recognition of the Confederacy.

Robert E. Lee’s decision to fight a battle at Antietam after the South Mountain operation is questionable. The Southern operational plan had been compromised when McClellan received a copy of Special Order 191, and Lee was fortunate that he was able to prevent the destruction of the Army of Northern Virginia in detail. Although McClellan’s command style lessened the direct possibilities of disaster, it was still a considerable gamble for Lee to risk one of the Confederacy’s principal armies on his reading of McClellan’s character. Lee had done well enough with taking the war into Maryland after the Second Manassas Campaign and capturing Harper’s Ferry. There may have been political reasons for risking a major engagement, but with its back to the Potomac River the Army of Northern Virginia faced the very real prospect of annihilation at Antietam. A more audacious Federal commander, with more attention to timing and command control than McClellan demonstrated, would have accomplished just that.

The counter argument may be that Lee knew his opponent, and that is certainly one of the marks of a great commander. Nevertheless, Robert E. Lee’s fundamentally aggressive nature would cause the South further difficulties in Pennsylvania the following year during the Gettysburg Campaign and during subsequent operations in the autumn of 1863. The basic fact remains that Robert E. Lee fought a masterly defensive battle at Antietam with limited resources. He shifted his available reserves at the proper moment and gave everyone present throughout the day of 17 September the very clear impression that Robert E. Lee was in complete control of his army and of the battlefield. However, it was still very much, as Wellington remarked regarding Waterloo, a very near run thing, and final disaster was only averted by the fortuitous arrival of A. P. Hill’s division from Harper’s Ferry.

George McClellan has been severely criticized by his contemporaries and by historians for the slowness of his strategic movements and for his customary battlefield caution. McClellan’s mission before 13 September was to keep the Army of the Potomac between Lee’s army and Washington – his primary task was the defence of the Federal capital. The capture of Special Order 191 altered the situation considerably, and McClellan was presented with the chance to destroy Lee’s formations one at a time if he moved swiftly. He ought to have ordered a night movement on the evening of 13 September, and as commander-in-chief he should have personally made certain that aggressive pursuit took place on the following day, after the engagements of South Mountain and Crampton’s Gap had been fought. Not only was the pursuit dilatory, but Franklin’s VI Corps was left slightly beyond Crampton’s Gap virtually without orders until early on 17 September. McClellan wasted a further day, 16 September, in and around the Antietam position. He should have attacked directly with whatever forces were immediately at hand. If not all the Army of the Potomac was yet on the field, and even if his unit commanders were unfamiliar with the terrain, the same could be said of conditions prevalent at that moment in Lee’s command. ‘The mud’, Napoleon remarked, ‘is the same for everyone.’ The opportunity was still available on 16 September to destroy elements of the Army of Northern Virginia, but McClellan failed to take advantage of it.

McClellan created a textbook tactical plan for the Antietam engagement. It was an operational conception that relied upon careful timing and close supervision. The uncoordinated nature of the assaults of I, XII and II Corps and the unconscionable delay in the advance of IX Corps have already been discussed – still, it very nearly worked. The Army of the Potomac fought extremely well between regimental and brigade level, but higher command control was lacking. The deficiency originated at the very top. McClellan remained on the eastern side of Antietam Creek through the majority of the battle, allowing his corps leaders to fight virtually their own separate engagements. He failed to supervise adequately the entirety of the Army of the Potomac. In the final analysis, however, it was the Confederate army that only escaped complete defeat by a narrow margin, and it was Lee’s army that was retreating into Virginia by 19 September. McClellan had saved Washington and driven the invading rebels back south. That is one issue. The failure of the Army of the Potomac to destroy the Confederate Army of Northern Virginia totally is quite another.

‘I feel that I have done all that can be asked’, wrote McClellan to his wife on 20 September, ‘in twice saving the country.’

The Battle of Antietam and Federal progress in halting the Confederate invasion of Kentucky that culminated at Perryville contributed in a dramatic fashion to altering the fundamental nature of the American Civil War. It became not only a conflict to preserve the Union but also a struggle to end the institution of Negro slavery in America. The destruction of the ‘peculiar institution’ had assumed the status of a moral crusade for many in the years before the War, although it is important to remember that in the nineteenth century it would not have been considered inconsistent to condemn the institution of slavery on moral grounds yet still have no interest in basic civil and social rights for the Black population as individuals. The Republican Party had argued for the elimination of slavery in Federal territories since 1856.

The election of Abraham Lincoln in 1860 instigated the American Civil War. The course of the conflict would not only retain the Republic, but it would also ultimately destroy slavery. The Emancipation Proclamation issued soon after the battle of Antietam was not without precedent. The Lincoln administration declared slavery illegal in the territories on 19 June 1862. In the spring of 1862, Lincoln informed Congressmen of the loyal slave-owning border states that he was considering emancipation, and the 2nd Confiscation Act of July 1862 declared that all slaves taken as military contraband were to be considered free by Federal authorities. In addition, Lincoln informed his cabinet in July 1862 that he was considering a general emancipation statement. Secretary of State William Seward and others advised him to wait for Northern battlefield victories. Antietam encouraged Lincoln to make public the Emancipation Proclamation in a presidential decree of 22 September 1862, to take effect from 1 January 1863. It freed all slaves held in those parts of the nation in open rebellion, that is basically in the Confederacy. The immediate effect in terms of the numbers of Blacks freed may have been minimal, but it cannot be denied that the basic character of the American Civil War had been altered.

Antietam changed the military character of the war as well. The struggle seemed to have lost its innocence, for the staggering casualty lists and the savagery of a single day’s fighting graphically illustrated that the war as an undertaking was a massive and serious concern. It would not be a conflict lightly pursued nor easily terminated. The American Civil War went beyond mere politics after Antietam. The War concerned itself with the maintenance of the Union, the destruction of Negro slavery, the survival of both Northern and Southern societies, and perhaps the alteration of the very fabric of the Republic. Antietam demonstrated to many participants that the events of which they were a part were not unimportant. Corporal Harrison Woodford of the 16th Connecticut, a veteran of Antietam, apparently thought so. He might stand for all the young men, living and dead, Northern and Southern, who fought in the Maryland Campaign in September 1862. Woodford wrote home to his sister on 26 September 1862, while his regiment was still encamped on the Antietam battlefield, asking her to remind his two younger brothers to assist their father in maintaining the family farm back in Connecticut. ‘Tell them they must be good boys and help father all they can,’ wrote Woodford. ‘I have gone to fight for their freedom and for their interests in the future.’



Excerpted from Antietam 1862: The Civil War’s Bloodiest Day by Norman S. Stevens.

Reprinted with permission from Osprey Publishing.

NORMAN S. STEVENS is a long time student of the American civil war and the author of numerous books, including Antietam 1862. He is currently a Major and assistant Professor of History at the Virginia Military Institute.

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