ANTIETAM, THE BATTLE OF THE. The Antietam flowing south into the Potomac above Harper's Ferry gives its name to the battle fought (Sept. 17, 1862) between the Federals under McClellan and the Confederates under R. E. Lee. After his incursion into Maryland Lee with three divisions had re treated from South Mountain behind the Antietam (Sept. i5), where he awaited the arrival of six divisions under Jackson from Harper's Ferry, which had capitulated at 8 A.M. that day. Jackson rejoined with three next morning. That afternoon Mc Clellan, who following slowly in pursuit had only reached the Antietam late on the r 5th, sent the I. Corps (Hooker) across by the bridge highest up the stream. About dusk Hooker came into collision with Hood's two brigades on the Confederate left. The XII. Corps (Mansfield) crossed at II :3o P.M., and encamped a mile in Hooker's rear. McClellan's plan was to make his main attack upon the Confederate left with the I., XII. and II. (Sum ner) Corps, supported if necessary by the VI. Corps (Franklin), whilst Burnside with the IX. Corps was "at Ieast to create a di version with the hope of something more by assailing the enemy's right." When one or both of these movements were "fully suc cessful," he intended to launch his reserve—V. Corps (Porter)— against Lee's centre.
Lee's position was fairly strong, extending over three miles from "the Burnside bridge" over the Antietam to a bend in the Po tomac. In the West Woods outcropping ledges of limestone pro vided excellent cover. But the line of retreat to the Boteler Ford below Shepherdstown, where alone the Potomac could be crossed, ran parallel to the right flank, itself somewhat "in the air." On the extreme ,left Stuart's cavalry occupied a ridge overlooking the Potomac; Jackson with two divisions held the turnpike and the woods on either side, with Hood's brigades in reserve; D. H. Hill's division continued the line southwards, and Longstreet's seven brigades stretched from Sharpsburg to "the Burnside bridge." Two cavalry regiments guarded the bridge below. Jackson's third division (Walker) was at first held in reserve behind the right flank.
Hooker's attack began at 5:3o A.M. on the 17th and was over two hours later. His corps was already retiring, when Mansfield's Corps advanced. Its attack ended about 9 A.M. One division had established itself in the West Woods ; Walker's division had rein forced Jackson. A little later Sumner with Sedgwick's division charged through the West Woods, but was taken in flank by McLaws's division, which with Anderson's had only that morn ing arrived from Harper's Ferry, and by Walker's, and was driven hack with a loss of over 2,000 men. By io:3o A.M. the fighting on Jackson's front was over and the Confederates had regained possession of the West Woods.
Further south French and Richardson of Sumner's Corps attacked D. H. Hill, who was reinforced by Anderson. Here the fighting lasted from Io A.M. to I P.M. Richardson on the left drove back Anderson and gained a position from which he en filaded "the Bloody Lane," a sunken road which Hill was holding against French. Hill's division broke, and if McClellan had allowed Franklin to advance across the turnpike, Lee's line might have been cut in two. Burnside only received the order to ad vance some hours after Hooker's battle began. After a pro longed struggle the IX. Corps carried the bridge about I P.M. Two hours later it advanced against Sharpsburg, which was de fended by one division only. It was rolling up the Confederate line and had reached the outskirts of Sharpsburg, when about 4 P.M. A. P. Hill's division, after a forced march from Harper's Ferry, came up from the Potomac and striking its left flank drove it back to the bridge.
With the defeat of the IX. Corps the battle of the Antietam ended. McClellan had fully 70,000 men on the field, but he kept one-third of his army out of the battle. The V. Corps remained in reserve all day ; only one of Franklin's brigades was seriously engaged. Federal casualties numbered over 12,00o. Lee lost be tween a fifth and a quarter of his army, less than 40,000 strong. Despite his losses Lee offered battle next day, but McClellan, though reinforced by two more divisions, allowed Lee to recross the Potomac that night without interruption.
The historian Ropes has written, "0f General Lee's manage ment of the battle there is nothing but praise to be said." He might have added, it has been suggested "of McClellan's man agement there is nothing but censure." The Northern commander made no adequate reconnaissance to find out the Confederate po sition or where the creek could be forded. The attack, instead of being simultaneous along the whole front, was made piecemeal; there were, in fact, five separate attacks at different hours. This is the more remarkable as one of the maps preserved in the official records shows that McClellan was in signal communica tion with his corps commanders' headquarters. Had the Federal reserves been led across Antietam creek by the bridge and fords near its mouth, Lee's sole line of retreat via Boteler ford might have been cut and his Army intercepted. (W. B. Wo.) See F. W. Palfrey, The Antietam and Fredericksburg (1882) ; E. P. Alexander, The American Civil War (1908) ; G. F. R. Henderson, Stonewall Jackson vol. ii. (1902) ; J. C. Ropes, Story of the Civil War, vol. ii.