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Chapter 9: "Corn Acres of Hell"
The banners of a revolution waved in the bright sunlight, marking a passage. Behind them, in ranks of four, Stonewall Jackson's soldiers waded into the river's shallows. "I never expect as long as I live," wrote staff officer Thomas G. Pollock, "to witness so imposing a spectacle." "Nobody spoke," explained Pollock, because "it was a time of great feeling." He spurred his mount into the current beside the moving column. Halting in the stream, Pollock turned in his saddle. As far as he could see stretched an unbroken string of infantrymen. "I felt," he told his father in a letter two days later, "I was beholding what must be the turning point of the war."
Before Pollock passed the vanguard of Confederate nationalism as it crossed into Maryland, at White's Ford on the Potomac River, north of Leesburg, Virginia. It was September 5, 1862, less than a week after the victory at Second Manassas or Bull Run. In two months, General Robert E. Lee and the Army of Northern Virginia had carried the war from Richmond's doorstep to Northern soil upriver from Washington. Perhaps, as the young staff officer believed, the conflict was following a new road.
Lee understood that an offensive beyond the Potomac was "attended with much risk." But, as he argued to President Davis on September 2, "The present seems to be the most propitious time since the commencement of the war for the Confederate Army to enter Maryland." Such a movement would give the Old Dominion a respite from the war's ravages, contended Lee, allow the Confederates to garner supplies and recruits from Maryland residents, and perhaps force the enemy into a crucial battle. If the operation proceeded well, the commanding general planned to extend the raid into Pennsylvania.
Despite the victory at Manassas, however, Lee's legions suffered from critical shortages on the eve of what could be a lengthy movement. They lacked shoes and clothing the Southerners "were the dirtiest men I ever saw, a most ragged, lean and hungry set of wolves," claimed a young boy who saw them enter Maryland. The operations during August also had outpaced the commissary. Lee anticipated that the army could seize supplies in the North, but if the Confederates met the enemy in battle, the low levels of ammunition and ordnance stocks could be critical to the combat's outcome.
The opportunity accorded the Confederates by their recent victory gave Lee the strategic initiative. With Jackson's command in the lead, the army of about fifty thousand men marched into Maryland. By September 6, Lee's entire force was camped at Frederick, where the Southerners paused until the 10th, while Lee, Jackson, and Longstreet formulated the operation's next phase.
The discussions among the army's three senior generals focused upon the Union garrison at Harper's Ferry. Lee wanted it eliminated as a threat to the army's communications and rear if he advanced into Pennsylvania. The enemy command of approximately fourteen thousand troops was vulnerable if the Confederates could seize the heights above the town. Lee proposed a division of the army to accomplish the task, but Longstreet, and perhaps Jackson, objected to the plan, arguing that the entire army should be used in the operation. Lee rejected the idea, and on September 9, issued Special Orders No. 191, which designated assignments for each of the army's nine infantry divisions and Jeb Stuart's cavalry.
Lee committed six divisions to the capture of Harper's Ferry. Jackson and three divisions would recross the Potomac into Virginia upstream from the village and seal the western approaches; two divisions would march through Pleasant Valley and secure Maryland Heights to the north of Harper's Ferry; and the final contingent would reenter Virginia to the east, occupying Loudoun Heights. Longstreet and two divisions, meanwhile, would cross South Mountain with the army's main wagon train, as the division of D. H. Hill acted as rear guard. With the surrender of Harper's Ferry, which Lee projected for September 12, the army's scattered units would reunite at Boonsboro or Hagerstown, Maryland, before advancing into Pennsylvania.
The Confederate army marched away from Frederick on the 10th. Lee had undertaken a bold gamble that counted upon a swift execution of his plans and the slow advance of the Union army from Washington. But the fates, it seemed, conspired against the Confederates. It was not until the 14th that the three elements of the army had closed on Harper's Ferry, having encountered delays attendant upon the movement of units, and some stiff enemy resistance on Maryland Heights. More critically to the army, the Federals had assailed D. H. Hill's troops on South Mountain during the 14th. Only a valiant stand by Hill's brigades and reinforcements from Longstreet prevented a possible disaster. That night, Lee prepared for a withdrawal from Maryland, informing a subordinate, "The day has gone against us and this army will go by Sharpsburg and cross the river."
Cheers resounded along the blue-coated column in a thundering of voices, with the news rolling back along the ranks like a well-timed volley "Little Mac is back!" Men shouted, leaped into the air, and tossed their caps in celebration. When John Gibbon announced it to his Westerners, "they were perfectly wild with delight," emulating their comrades by hurling their black hats into the air. It seemed inexplicable, perhaps, but George McClellan's hold on the hearts of his men was undeniable. As one of them said tersely, "A Deliverer had come."
In the wake of the bitter defeat at Second Bull Run, the Federals needed a "Deliverer." Even John Pope had recognized the signs of a dispirited army, informing the War Department on September 2 that "unless something can be done to restore the tone to this army it will melt away before you know it." Within the army, the officers and men blamed Pope "a complete failure," in Gibbon's words and Irvin McDowell.
In Washington, Abraham Lincoln reacted to the crisis by turning to McClellan. The president did so with reluctance and against the protests of the cabinet. The department heads believed that McClellan had imperiled Pope's army deliberately by his slow withdrawal from the Peninsula. Some cabinet members tried to persuade Lincoln to dismiss the general from the service, but the president refused. As Lincoln saw it, he had no other choice and gave McClellan command of the Army of the Potomac and Pope's Army of Virginia. Like the army, Lincoln hoped that the Union had its savior.
While the army camped around Washington, McClellan responded to the situation with a renewed spirit and energy. He rode through the bivouac sites for the men to see him, acknowledging their cheers by doffing his cap. He restructured the army into three wings, assigning two corps each to two wings and a corps and a division to the third. As for Robert E. Lee's Confederates, McClellan accepted slowly the intelligence reports and civilian accounts that placed the Rebels at Frederick. Characteristically, however, he believed the reports that estimated his opponent's numbers at 120,000, nearly three times Lee's actual strength. On September 7, the Union commander began shifting more of his units into Maryland, northwest of the capital, and relocated his headquarters to Rockville. Two days later, the 85,000-man army began the pursuit of the enemy.
Federal units filled Maryland roads along a broad front, marching deliberately in the heat and dust for three days. On September 12, two days after the Confederates had departed, the advance elements of McClellan's right wing entered Frederick to the jubilation of its residents. More troops filtered in throughout the day and on the 13th. The soldiers bivouacked in the fields outside town, where on the latter day, two members of the Twenty-seventh Indiana discovered a copy of Lee's Special Orders No. 191, wrapped around three cigars. They gave it to their company commander, who carried it to regimental headquarters. From there, it passed through the chain of command to McClellan.
When McClellan read the contents, he grasped its importance at once. In fact, he held in his hands one of the greatest intelligence finds in American military history. He wired Lincoln at noon, "I think Lee has made a gross mistake, and that he will be severely punished for it....I have all plans of the rebels, and will catch them in their own trap if my men are equal to the emergency." Later in the day, Brigadier General John Gibbon visited his old friend at army headquarters, and according to Gibbon in his recollections, when McClellan saw the subordinate, he waved the copy of the order and said, "Here is a paper with which if I cannot whip Bobbie Lee, I will be willing to go home." McClellan then added, "Tomorrow we will pitch into his centre and if you people will only do two good, hard days' marching I will put Lee in a position he will find hard to get out of."
While McClellan and Gibbon conversed, the latter's brigade was camping along the Monocacy River, southeast of Frederick. As noted previously, the Wisconsin and Indiana troops had welcomed enthusiastically McClellan's return. At Brawner's Farm and Second Bull Run the war had overtaken them at last, and they had learned, as a sergeant put it, the Rebels "fight like so many devils." Since their initial days at camps Randall and Morton, they had waited for their time, and although the Second Wisconsin had experienced it early, the other three regiments had spent a year in the army, grumbling constantly that the conflict would elude them. But the fury had embraced them, extracting a price of over nine hundred comrades or nearly one half of the brigade's membership.
Despite the casualties and the campaign's rigors, Gibbon told his wife on September 3 that the brigade was in "excellent condition." With the rest of the army, the Westerners marched four days later. The 7th was a Sunday, and a Hoosier soldier complained that there was "nothing to remind us...of the holy Sabbath, nothing but long lines of soldiers, weary and faint traveling along through heat and dust." During the next five days, they passed through Mechanicsville, Lisbon, and New Market. "This is beautiful country," a Wisconsinite noted, "with great farms and beautiful girls." An unusually high number of men fell out of the ranks. A surgeon believed that the proportion who straggled exceeded that of any previous march, but once they reached Frederick, he claimed, "the spirits of the men began to assume more buoyancy."
One of those whose spirits were not renewed by the arrival at Frederick was Captain Edwin Brown of the Sixth Wisconsin. He commanded Company E, which had been reduced to thirty-four members. "The Rebels are in force in Maryland, we are 'massing' to meet them," Brown informed his wife, Ruth, in a letter of September 13. "I am weary & sick if the enemy was off from our soil I should go to Hospital. Honor requires that every one who has any patriotism left should meet the insolent foe. Should I live to drive them out of this State & away from Washington, I will have rest at some rate." Continuing, he admitted, "I feel as though I was alone." Brown ended with an unusual, "Good Bye."
Captain Brown and his comrades in Gibbon's brigade marched at 6:00 A.M. on September 14, crossing the Monocacy River, before entering Frederick. Like other units before them, the Westerners received the populace's cheers. They followed the old National Road through Middletown, halted to eat a midday meal, and about three o'clock in the afternoon approached South Mountain, from whose eastern slope smoke could be seen and the sounds of combat heard. Gibbon soon received an order to report with the brigade to wing commander Major General Ambrose E. Burnside.
Since mid-morning the Federals had been ensnared in a fight for the 1,300-foot-high hill, held by D. H. Hill's five Confederate brigades. Hill's men guarded Turner's Gap, through which passed the National Road, and Fox's Gap, a mile to the south, where the Old Sharpsburg Road crossed the mountain. Three smaller roads branched off from the main routes over South Mountain. The terrain favored the defenders, however, with ravines, hollows, and knolls covered with trees, underbrush, and thick, entangled patches of mountain laurel. Hill was one of Lee's finest combat officers, and the Confederate army needed such a man on South Mountain on this day.
By the time Gibbon's brigade reported to Burnside, the combat on South Mountain extended from south of Fox's Gap to north of Turner's Gap. McClellan had committed eighteen brigades in seven divisions to the fighting, while Hill had received reinforcements from Longstreet, bringing the total of Confederate brigades engaged to fourteen. At four o'clock, the entire Union First Corps, except for Gibbon's brigade of John Hatch's division, launched an assault against the Confederate left flank north of Turner's Gap, using Old Hagerstown Road and a farm road. Wanting to assist the corps, now commanded by Major General Joseph Hooker, Burnside directed Gibbon to advance directly up the National Road toward the front of Turner's Gap, or as he stated in his report, "for the purpose of making a demonstration upon the enemy's center."
Gibbon aligned his four regiments on both sides of the old highway upon which countless numbers of Americans had traveled west. The Nineteenth Indiana deployed south of the road in a battle line, with the Seventh Wisconsin parallel to the Hoosiers north of the roadbed. In double columns the Second Wisconsin formed behind the Nineteenth and the Sixth Wisconsin behind the Seventh. Each of the latter units detached two companies to the front as skirmishers, while an Indiana company covered the attackers' left flank as skirmishers. Before the Westerners advanced, ten officers and forty-one enlisted men of the Second Wisconsin "were compelled" to fall out because of exhaustion and sickness. If other men in the remaining regiments did likewise, it went unreported.
The eastern face of South Mountain appeared dark green, even black, as the sun sank beneath the crest when the Westerners moved forward. Steadily, in ranks worthy of troops in a review, the roughly twelve hundred Federals pressed ahead through open fields. Behind them, Gibbon watched their progress with pride, writing later that "the occasion was one to exhibit admirably, the drill and efficiency acquired by the brigade whilst lying at Fredericksburg." To the demanding brigadier, they looked like Regulars.
On the mountain, Confederate artillery crews saw them coming and opened fire. One shell exploded in the Second Wisconsin, killing four and wounding three. Ahead of the Nineteenth Indiana, Rebel skirmishers fired from the windows of a farmhouse. Colonel Solomon Meredith requested artillery support, and a section two guns of Battery B, Fourth U.S. Artillery deployed in the road, sending a round into the upper story of the house. The Rebels scattered, Meredith reported, in a "general stampede." When the Hoosiers passed through the farmyard, they grabbed turkeys and chickens, according to the reminiscences of one of them. The owner protested the thievery, but the soldiers rebutted that the fowl were "obstructing our forward movement."
From among the trees, Confederate infantry triggered a volley into the Nineteenth. The Southerners were Alabamians and Georgians under Brigadier General Alfred H. Colquitt. They had held the position across the road all day, spared from the combat until now. They knew who the Federals were, calling them "damned black hats." Most likely, they knew that it would be a fight.
"The fire became general on both sides," Meredith stated. His Indianans unleashed a volley, cheered, advanced, and repeated the sequence. The colonel thought "it was a most magnificent sight" to witness his men moving forward with shouts. Colonel Lucius Fairchild brought up the Second Wisconsin, joining the Hoosiers in the combat. A member of the Second described the Confederate artillery and infantry fire as "murderous." Shielded by trees and stone walls, Colquitt's Rebels held their position.
North of the National Road, the Seventh Wisconsin crested a knoll and were blasted at a range of forty yards by the Twenty-third and Twenty-eighth Georgia. A Federal described it as "a most terrific fire," adding that "it seemed no one could survive." The Georgians enfiladed the Seventh on both flanks. The Yankees clung to the knoll, firing as rapidly as they could reload.
With the explosion of musketry in front of the Seventh, Lieutenant Colonel Edward Bragg rushed the Sixth Wisconsin forward at the double quick. The Sixth's right wing came into line on the Seventh's right flank, with the left wing stacked behind it. Bragg's men relieved the pressure against the Seventh, engaging the Twenty-eighth Georgia. Before long, however, Gibbon ordered Bragg to turn the Confederate flank.
Bragg was, in the estimate of Major Rufus Dawes, an officer of "a remarkable quick conception and instant action." When he received Gibbon's directive, Bragg went to Dawes, who commanded the right wing, and instructed the major to have his men fire a volley and then lie down. "I am going over you," Bragg said, referring to the left wing. Dawes complied, and Bragg led the other half of the regiment up the slope, ordering his troops to fire a volley and fall to the ground. Dawes followed with his wing and repeated the tactic. The Sixth ascended the mountain, with one wing leapfrogging the other. "In a long experience in musketry fighting," Dawes contended later, "this was the single instance I saw of other than a fire by file in battle."
The Sixth "poured volley after volley into the enemy." The gunfire on both sides was "incessant and forcible." Sergeant George Fairfield believed that "the artillery roared to beat anything I had yet heard." South of the worn roadway, the Second Wisconsin wheeled to the right, raking the flank of the Georgians across the road. It was so dark that neither opponent could see each other. The men aimed at the rifle flashes. The "sides of the mountain seemed in a blaze of flame," avowed a Federal.
The combat raged in the darkness until nine o'clock. The Second Wisconsin expended all its ammunition, and Colonel Meredith brought forward the Nineteenth Indiana to relieve the Second. In the Sixth and Seventh Wisconsin, the men searched the dead and wounded for cartridges. When Gibbon learned of the situation, he ordered a cease-fire, but admonished the officers to "hold the ground at the point of the bayonet." In a final spasm, the Georgians crept toward the Sixth and Seventh only to be lashed by a final volley. Bragg's men emitted three cheers, and as the lieutenant colonel said, "the enemy was no more seen."
Before midnight, troops from Massachusetts, Minnesota, and New York replaced Gibbon's men, except for the Sixth Wisconsin, at the front. It was not until eight o'clock on the morning of the 15th before Bragg's regiment filed off the mountainside. The engagement had cost the "damned black hats" 37 killed, 251 wounded, and 30 captured or missing, for a total of 318, a quarter of the brigade's strength. Among the dead was Captain Wilson Colwell of the Second Wisconsin. Described as "a general favorite of the regiment," Colwell fell while commanding the skirmishers. "His place can hardly be filled," reported Colonel Fairchild.
When the brigade had passed through Frederick earlier in the day, Private George Miles of Company A, Sixth Wisconsin remarked to comrades that he had had a premonition of his death. His fellow soldiers reassured him otherwise, but when the regiment formed for battle, some of them asked Captain David Noyes to assign Miles to other duty. Noyes approached the private, who refused, saying that he would do his duty. As the wings of the regiment climbed the mountain, fighting the Georgians, the Reedsburg, Wisconsin, volunteer was killed.
In a letter to his wife, written the next day, Gibbon confided, "Every one, from Genl. McClellan down, speaks in the highest terms of my gallant Brigade and I of course am proud." First Corps commander Joseph Hooker had not witnessed the struggle between Gibbon's and Colquitt's troops, but stated subsequently that the Westerners' list of casualties "speaks for itself." Wing commander Ambrose Burnside, who watched the fighting with McClellan, described it as "a most brilliant engagement." In his report, Gibbon boasted, "The conduct of the officers and men was during the engagement everything that could be desired, and they maintained their well-earned reputation for gallantry and discipline acquired in the engagements of the 28th and 30th of August."
In the fields of Brawner's Farm, on the crest of Dogan Ridge, and at the base of South Mountain, the Black Hat Brigade, as the Wisconsin and Indiana troops had come to be known in each army, demonstrated how inexperienced combat soldiers could answer the fearful summons. Imbued with patriotism and tempered by discipline and training, the Westerners had stood amid the terribleness with a valor that had marked them among both comrades and enemies. They were warriors now, these men in tall, black hats.
During the battle at South Mountain, as Gibbon directed the brigade's movements, the general stopped one of his men. The soldier had been wounded earlier in the action, and with an arm in a sling and a rifle in the other, was returning to his regiment. "My man where are you going?" asked Gibbon.
"Back to my regiment, sir," replied the brigade member.
"But you can't handle your musket in that fix," Gibbon rebutted.
"Yes I can, sir," the Westerner affirmed.
Gibbon let him pass to the front, and as he informed his wife, "I had nothing more to say."
The Confederates dragged themselves off South Mountain during the night of September 14-15. In Boonsboro, at the western base of the mountain, Robert E. Lee conferred with several of his ranking subordinates. "After a long debate," the officers decided to retreat to Sharpsburg, Maryland, on the 15th. Lee anticipated that the army would have to abandon the operation north of the Potomac River, and the route through Sharpsburg led to a good ford. But later that night, Lee received a message from Stonewall Jackson, who indicated that Harper's Ferry would fall to his troops within a day. Perhaps the army could hold at Sharpsburg until its scattered divisions could be reunited.
While the troops with Lee marched to Sharpsburg on the morning of the 15th, Jackson sealed the fate of the Union garrison at Harper's Ferry. Southern artillerists on the heights above the town opened fire once the morning's fog lifted. Union gunners responded, but after an hour, the Federals requested a truce. Before nine o'clock the garrison's commander surrendered the post, 12,500 troops, 73 cannon, thousands of weapons, and hundreds of wagons and animals. All that had eluded the grasp of the Rebels was a 1,300-man cavalry contingent that had escaped during the preceding night, finding an unguarded road below Maryland Heights.
Jackson hurried a letter to Lee, informing the army commander of the victory. Much had to be done at Harper's Ferry, however, before Jackson could rejoin Lee at Sharpsburg. The Confederates feasted on the enemy's foodstuffs as they had at Manassas Junction on August 27, while officers began the process of paroling prisoners and starting the ordnance supplies and arms south. Leaving A. P. Hill's division behind to finish the details, Jackson started with his other two divisions before midnight for Sharpsburg. The Southerners marched all night without cessation, crossing the Potomac at Boteler's Ford near Shepherdstown, and arriving late on the morning of the 16th at Sharpsburg, seventeen miles from Harper's Ferry. Lee greeted Jackson and escorted his subordinate to headquarters, where they discussed the situation.
Lee's decision to seek an engagement before the army returned to Virginia was arguably the worst of his career. The terrain provided few natural advantages to the defenders. If his army suffered a defeat, it would have to retreat across the Potomac about four miles to the west. The town lay less than a mile west of Antietam Creek amid rich limestone soil. The encircling farmland undulated from the crests of ridges to the bottoms of hollows. Hills of various heights jutted above the creek's western bank while rock outcroppings and woodlots splotched the fertile fields. For decades the land had nourished farm families and townsfolk, but now if Lee were to make a stand before he abandoned Maryland, it had to be here on ground more suited for the labors of a farmer than those of a warrior.
The strategic and tactical weaknesses of the position were compounded by the reduced numbers in Lee's army. Straggling was, according to a historian, "unprecedented" during the campaign. Men abandoned the ranks in droves, impelled by the hardships and by the invasion of Northern soil. The troops suffered from heat, dust, lack of shoes, and the collapse of Lee's commissary. A Shepherdstown woman who saw the Rebels pass through her town testified later to the condition of the army. "When I say that they were hungry," she asserted, "I convey no impression of the gaunt starvation that looked down from their cavernous eyes." She watched soldiers from both sides march by for four years, but during the Maryland campaign, "never were want and exhaustion more visibly put before my eyes, and that they could march or fight at all seemed incredible."
A considerable number had either refused to cross the Potomac, or once in Maryland, returned to Virginia, believing that they had enlisted to defend their homeland and not to carry the conflict beyond its borders. A critical shortage of officers hampered efforts to enforce march discipline and to keep the stragglers or the disenchanted in the ranks. While precise figures cannot be determined, the Confederate army at Sharpsburg, when all units were on the field, probably numbered fewer than forty thousand, perhaps as low as thirty to thirty-five thousand.
A recent estimate has calculated the average Confederate regimental strength at 166 and comparative Union numbers at 346. In the Stonewall Brigade, the figures were starkly worse. Jackson had detached the Second Virginia and assigned it to provost duty in Martinsburg, Virginia, reducing the brigade's regiments to four. Colonel Andrew Grigsby commanded the Virginians, with a lieutenant colonel, a major, and two captains serving as regimental commanders. The brigade's reported strength at Sharpsburg was 250 officers and men, an average of slightly more than sixty per regiment.
Private John Garibaldi of the Twenty-seventh Virginia claimed in a letter written after the battle, however, that only a dozen members were with the regiment on the field at Sharpsburg. When Jackson's troops returned to Maryland after the fall of Harper's Ferry, most of the Twenty-seventh's men "never went across the river," according to the private. Although Garibaldi was absent during the campaign, he learned this from comrades upon his return to the regiment. If the number is accurate it indicates the breakdown of discipline in the unit, the campaign's hardships, and/or the Valley men's refusal to risk their lives in an invasion of Union territory. In less than five months, the Stonewall Brigade had seen its strength reduced by more than ninety percent. Casualties exacted a share, but the majority of losses had resulted from desertion.
On ground that favored an aggressive opponent, with an army outnumbered two to one, and with his back to a river, Lee stood at Sharpsburg. If he held the field, he could achieve little more than a drawn battle, but if the Federals broke the Southern lines, Lee risked the destruction of his army. He explained his decision after the war, stating that "it was better to have fought in Maryland than to have left it without a struggle." He was convinced also that he could defeat his opponent, George McClellan.
Boonsboro, Maryland, sat hard by the western foot of South Mountain. A small village of stone, log, and clapboard houses, Boonsboro framed the National Road as it debouched from the mountain through Turner's Gap. Its residents had heard the sounds of battle tumble down the mountainside and had watched Confederate troops race up the road toward the gap on September 14. During the ensuing night, they had witnessed the retreat of the Southerners. Now as September 15 lengthened, ranks of blue-coated soldiers descended South Mountain, pursuing the Rebels toward Sharpsburg, seven miles to the west.
The townsfolk with Union sympathies welcomed the passing troops. Major Rufus Dawes remembered that a "respectable old gentleman" approached him and exclaimed, "We have watched for you, Sir, and we have prayed for you and now thank God you have come!" When George McClellan clattered into the village, amid a cloud of staff officers, the civilians joined the troops in cheering the general. Earlier, he had telegraphed the War Department, stating, "I am hurrying everything forward to endeavor to press their retreat to the utmost." McClellan added that "the morale of our men is now restored."
Throughout the 15th, the Army of the Potomac closed upon Sharpsburg. A member of the Black Hat Brigade reported that as the Westerners marched past troops from the Second Corps their fellow soldiers opened ranks and presented arms in a salute to the brigade. By mid-afternoon, John Gibbon's regiments and many units of the army were halted in fields along the Boonsboro-Sharpsburg road. On the hills west of Antietam Creek, Confederate artillery and infantry barked at any Union troops who appeared across the stream. McClellan's aggressiveness at South Mountain had surprised Lee, who learned only later of the so-called Lost Order. The Confederate commander resorted to a bold stand on the 15th, testing his opponent's determination while he waited for his army's scattered units to reconcentrate at Sharpsburg.
Lee's bluff succeeded, and resuming his cautious generalship, McClellan and the army bivouacked for the night beyond the creek. Fog shrouded the ground on the morning of September 16, delaying McClellan's examination of the enemy position. Once the mists cleared, he studied the terrain west of the creek from his headquarters at the Philip Pry residence, situated on a knoll north of the Boonsboro road. Although the general could acquire only a limited knowledge of the ground and Lee's troop dispositions from this vantage point, he fashioned an offensive plan for the 17th. He decided to strike with his main assault force Lee's left or northern flank, where the terrain appeared favorable to such a maneuver. On the Confederate right, where the hills abutted the creek, McClellan intended to force a crossing at Rohrbach Bridge, either as a diversion or as a full-scale attack. If the flank movements succeeded, he would crush Lee's center astride the Boonsboro road. Once more, however, McClellan miscalculated his opponent's strength, inflating the numbers.
McClellan committed three corps First, Second, and Twelfth to the attack north of Sharpsburg. Late in the afternoon of the 16th, the corps began the march toward their assigned areas, crossing the creek at Upper Bridge. Major General Joseph Hooker's First Corps, including the Black Hat Brigade, led the movement. Hooker's van brushed aside Rebel skirmishers, angling northwest and halting in the fields between the Joseph and Samuel Poffenberger