Following the bloodletting of the September 17, 1862 Battle of Antietam the exhausted Army of Northern Virginia commanded by General Robert E. Lee was left with no choice but to retreat back into the safety of Virginia. Lee did so the night of September 18 after lying all day on the battlefield waiting and hoping the Union Army of the Potomac would counterattack; when no attack came, Lee chose to withdraw back across Boteler's Ford on the Potomac, seen above. Also known as Pack Horse Ford, this had been the way the troops of the command of Maj. Gen. Thomas J. "Stonewall" Jackson had entered Maryland from their successful capture of Harpers Ferry only four days earlier. http://civilwartalk.com/threads/the-battle-of-harpers-ferry-jacksons-greatest-victory.104193/ The division of Maj. Gen. Ambrose Powell Hill had also crossed here during the battle in time to save Lee's right flank as described on the markers at the ford. Likely exhausted himself, the Confederate commander rather carelessly entrusted the security of the river crossing to one of the senior members of his staff, Brig. Gen. William Nelson Pendleton, nominal commander of the army's artillery reserve. Pendleton placed some of his guns near the ford, supported by two worn-out brigades of infantry numbering only some 600 men. That evening however, a regiment of Federals crossed the river at the ford achieving complete surprise over the startled Confederates and capturing a battery of guns in the process. Pendleton, above at right, although a military man much earlier in his life had been an Episcopal priest in Lexington, Virginia, at the war's outbreak and briefly commanded the Rockbridge Artillery Battery attached to the Stonewall Brigade at the Battle of Bull Run in 1861. He had no experience directing infantry, which he at first vainly ordered about before taking flight to the headquarters of his commanding general. Here he found an incredulous Lee and an angry Stonewall Jackson, center, who demanded to know the strength of the Federal force which had supposedly just captured (according to Pendleton) all 44 guns of the army's artillery reserve. Upon learning this was likely no more than a reconnaissance, Jackson sent word for the division of A. P. Hill, seen at left, to reverse its course back to the Potomac. The Federals were members of the V Corps commanded by Maj. Gen. Fitz-John Porter, whose men had largely sat out the battle at Antietam in the Union center. They had been deployed at the Middle Bridge crossing of Antietam Creek by the Boonsboro Pike where they had crossed the bridge and skirmished with a small body of Confederates. As some of the freshest troops in the army they had led the short pursuit to the Potomac where Porter deployed his considerable artillery and that of the army's reserve as shown on the map above. Porter, at left above, sent the regiment which had frightened Pendleton so badly, but recalled them for a larger effort the following morning, September 20. The division of Brig. Gen. George Sykes, above right, included a small brigade of U. S. Regular Army battalions which pushed forward from the ford up the bluffs on the south side of the river while another brigade under Col. G. K. Warren followed them across. A third brigade from the division of Brig. Gen. George Morrell led by Brig. Gen. James Barnes, at center above, also crossed and took position on Sykes' right nearer to Shepherdstown. Col. Lovell's brigade of Regulars soon ran into the rapidly approaching Confederates of A. P. Hill, who had been ordered by Jackson to recover Pendleton's captured guns and drive the Federals into the Potomac. The outnumbered Regulars quickly withdrew to the riverbank in the area above from which Sykes decided to abort the operation and recross Boteler's Ford to the Maryland shore. Central to the Union position along the river was the ruin of a cement mill owned by Confederate Congressman Alexander Boteler which had been burned by Federals the previous year. The mill had been an extensive operation, boasting a large lime kiln, warehouses, and an office building as seen here. The units of Sykes division got safely across the ford, but Barnes' regiments weren't so lucky; farther to the right, they were forced back into the mill ruins where they found a lesser crossing on the mill dam below. The unlucky 118th Pennsylvania Infantry, dubbed the Corn Exchange Regiment because of its sponsorship by that financial consortium, was in its very first battle where its members soon discovered they had been issued defective Enfield rifles. (From the description of their troubles it's likely the Enfields either had mainsprings too weak to properly power the hammers; or else, improperly fitted hammers; either way it seems they wouldn't pop the percussion caps.) The hapless green troops were indeed driven into the river at the dam as Hill's Confederates fired down on them as they floundered in the water staining it with their blood. The battle was over in short time with a resounding victory to crown the otherwise disappointing and devastating Confederate invasion of Maryland. Jackson's quick response had for the time ended any pursuit by the Federals and inflicted another 71 killed, 161 wounded, and 131 missing to the losses of the Maryland Campaign; at least 269 of those casualties were in the Corn Exchange Regiment. Confederate losses had been 261 men killed or wounded. Perhaps the greatest loss was to the reputation of William N. Pendleton, about whom one of his artillery lieutenants likened to an elephant: "We have him & we don't know what on earth to do with him, and it costs a devil of a sight to feed him."