At 4:00 p.m., July 2nd, 1863, two divisions commanded by General James Longstreet finally stepped out across the Emmitsburg Road to attack the Union Army of the Potomac's Third Corps. Longstreet's advance was the culmination of a frustrating, delay-plagued day for General Robert E. Lee and the Army of Northern Virginia. As early as 1870, Longstreet's critics began charging him with failing to attack at dawn per Lee's original orders, and costing Lee the battle and, by extension, the Confederacy the war. The "Dawn Attack" order was in fact never issued: the story was a complete slander against Longstreet, who, with his maverick politics and caustic comments, made a fair number of enemies of his old comrades in arms. However, even many of his stoutest modern defenders admit that the attack started late, and that delay effected the outcome. The attack plan was based on a faulty reconnaissance conducted by an engineer on Lee's staff early in the morning, and the approach march conducted over a route that was supposed to be concealed from Federal eyes, but proved not to be. Longstreet's irritation was manifest, especially after the entire column had to be turned around and marched back the way it came. Finally, as they neared the intended deployment area, Longstreet and his divisional commanders discovered that the Federal troops barred the way. The Union dispositions were nothing like what they had been led to expect. 

    Certainly, these factors are not signs of a smoothly functioning Army of Northern Virginia. Did they really cost Lee the battle, however? The story of the dawn attack orders, the flank march, and late start to the attack have been told many times - from the Confederate perspective. There is another side to the story,for the Union Army was having its own problems that effected the fighting, none of it good for the Federals. To fully understand the impact of Major General Daniel E. Sickles' unilateral advance, we need to examine three things: the terrain itself, the forces deployed to cover that ground, and the disrupting effect Sickles' advance caused when Meade tried to shore up the resulting line. When Sickles elected to advance his corps more than three quarters of a mile without orders, he disrupted the meticulous defensive preparations of his own commander, Major General George G. Meade, and threw open a wide window of opportunity for the Confederates that had not previously existed. Edwin Coddington, one of the most respected historians to have written about the battle, concluded that "Longstreet could not have hit the Union left flank at a more inopportune time for Meade..." ^[1]

    After the war, Sickles justified his advance on the grounds that the portion of the line Meade assigned to him was more a hole than a ridge, and untenable if the Rebels seized the high ground directly to his front, dominated by the Sherfy Peach Orchard on its crest. Certainly in relationship to where his men camped the night before, Sickles was correct. The Peach Orchard stood at about 590 feet above sea level, while the Trosle farmhouse stood at 530 feet, and Plum Run lower still, below the 520 foot contour. ^[2] With high ground some 70 feet higher less than 500 yards in front of his location, Sickles had a right to feel uneasy if that were actually where Meade wanted to place him. Meade, however, was a better soldier than that. 

Theportion of the line Meade intended Sickles to occupy was behind Sickles' campsite, where the southern extremity of Cemetery Ridge extended to the foot of Little Round Top. The night before Brigadier General John W. Geary, commanding the Second Division, Twelfth Corps, was ordered to hold this line from the left of the First Corps to the high ground of Little Round Top. ^[3] This line, while still slightly lower than the Peach Orchard, rose considerably higher than the Plum Run Valley, ran straight south. The Round Tops provided a secure anchor for the Union southern flank that would be hard to turn, and managed to avoid any awkward angles or bends. Most of it stood at the 560 or 570 foot contours, not very much lower than the 590 foot elevation of the Peach Orchard itself. Of course, at 670 feet, Little Round Top towered above almost everything but its larger namesake to the south.

    By contrast, the Peach Orchard line angled off to the southwest. From the Klingle house on Emmitsburg Road, the distance back to Cemetery Ridge is just under 1100 yards. From the Peach Orchard, that same line measures just over 1500 yards, and line from the Peach Orchard to the summit of Little Round Top runs almost 1800 yards, just about a full mile. This diverging angle ofthe Peach Orchard line created aserious deployment problem for any force that tried to defend it, in that the left flank of any such force would be extended invitingly toward the enemy, begging to be attacked. Moreover, the ground generally continued along the Emmitsburg Road in a fairly level sweep, with no single anchoring point. This angle all but invited a Confederate flanking movement in a way that Big Round Top, with rugged slopes, no roads, and heavy tree cover discouraged. The only solution to that problem was to bend any Peach Orchard defensive line back sharply toward the Round Tops, creating a different problem, a dangerous angle that would be exposed to attack from two directions at once. 

Nor were angles the only worry. The overall length of the two lines should have been a critical concern. The Third Corps’ intended line was just under a mile in length, about 1600 yards. Sickles claimed that the Third Corps' 10,000 men were not sufficient to hold that length of line effectively. ^[4] This claim does not bear up to scrutiny. 10,000 troops were sufficient to fully man the mile long length of the intended line while still leaving Third Corps strength for reserves. ^[5] The line he finally adopted, however, was twice as long at nearly 3500 yards. He never explained this dichotomy: how could a command that he claimed was over-extended at a mile successfully defend nearly two miles? 

    Instead, Sickles' main concern was that the Peach Orchard, if seized by the Rebels, would dominate his own designated position, allowing the Confederates to bring up artillery and savage his troops. One much speculated reason for this fear was Sickles' own experience at Chancellorsville, only two months before. The Third Corps had been forced to give up an exposed salient at Hazel Grove, a piece of elevated, open terrain which the Confederates promptly occupied. From there, Rebel cannon did make life miserable for the Third Corps. If Sickles was indeed recalling Hazel Grove when he gazed at the Peach Orchard, his eye missed several important differences. The first was that at Hazel Grove, the Confederates could use converging fire to concentrate on the Federal line near the Chancellor house; here, the opposite was true. Any Rebel battery the deployed along the Emmitsburg road was subject to converging fire from Union artillery ranged along the entire length of Cemetery Ridge and Little Round Top. The second was the presence of substantial wooded areas both along the intended line and down in the low ground of his campsites. This tree cover would have enabled Sickles to conceal much of his command from enemy observation and fire from the Peach Orchard, and give his skirmishers cover as they sniped at any enemy artillery deployed along in the open fields along Emmitsburg Road. More experienced officers saw the Peach Orchard for what it was; not a dominating position at all, but instead contested ground, that could be controlled by the Union artillery arrayed all along the Cemetery Ridge line. ^[6]

    Perhaps the single largest historical controversy of the war was that between Confederate General James Longstreet, whose corps attacked the Peach Orchard that afternoon, and a number of other former generals who after the war emerged to defend the ideals of the Confederacy and its heroes, Lee chief among them. Longstreet had the temerity to criticize Lee for Gettysburg, and was pilloried for it. His attackers were led by three other Army of Northern Virginia generals: Jubal Early, William N. Pendleton, and Fitzhugh Lee. Virginians all, these men were instrumental in preserving the story of the Confederacy through the Southern Historical Society Papers, and via those papers managed to create a fiction that Longstreet was intended to attack at dawn, and only his own recalcitrance robbed Lee and the South of a crushing victory. This story is a complete fabrication, but it came to dominate literature of the war well into the 1960s, when modern authors began to refute it. The full details of this contest fill up whole books, and are far beyond the reach of this article, but implicit in that charge is a critical concept that is often missed; The idea that Meade's flank was vulnerable through most of the day, and that only Longstreet's tardiness gave Meade time to realize his peril and reinforce that sector. In reality, that Union flank was never left unguarded. Meade kept strong forces there all day, and only Sickles' unilateral advance disrupted that stance. A survey of the troops available on that flank at various times of the day reveal the full story.

    At dawn, Meade had a variety of troops near the Round Tops. Buford’s Cavalry Division was the first line of defense. Buford had camped his men along the Emmitsburg Road near the Peach Orchard the night before, and established a line “with pickets extending almost to Fairfield.” ^[7] With 2700 men in two brigades, Buford had ample force to both detect any Rebel approach and delay it significantly. ^[8] Geary’s Division of Twelfth Corps, 4000 men strong, had been sent the night before to hold that portion of the Cemetery Ridge line later designated for Sickles, and extended as far south as Little Round Top itself, with two regiments on the crest of that hill. Part of the Third Corps was camped just in front of and to the right of Geary’s men, with four of its six brigades present, adding 7000 men to the defense. Finally, Major General Winfield S. Hancock’s entire Second Corps - temporarily under the leadership of Major General John Gibbon - was camped along the Taneytown Road just behind and to the south of Big Round Top. The Second Corps had about 11,000 men, and was close enough to support Geary and or Sickles almost immediately if they were attacked. In summary, at first light Meade had 2700 cavalry and more than 22,000 infantry and artillery either in place to defend his left flank or close enough to rush to support if attacked. 

    By mid-morning, those dispositions had changed somewhat. Buford was still in place, as was Sickles. However, Geary’s Division had departed to rejoin its own corps on the right flank, and the Second Corps had moved up the Taneytown Road to occupy the center of Meade’s line. Geary’s men left some time before 7:00 a.m. after being relieved by Third Corps troops. The Second Corps had begun filing up the Taneytown Road behind Sickles somewhat earlier, at around 6:00 a.m. Certainly by 8:00 a.m., both forces had departed. They were replaced by the remaining two brigades of Third Corps, up from Emmitsburg, who reached Sickles by about 9:00 a.m. with 3400 more men. Additionally, Meade had the Fifth Corps moved to Granite Schoolhouse Lane, a small roadway that stretched between The Baltimore Pike and Taneytown Road. This location was ideally suited for a reserve force to reinforce either flank or the center of Meade’s line, depending on the threat. By about 9:00 a.m. two divisions of Fifth Corps were available along this path, 7500 men strong. ^[9] TheFifth Corps was less than eleven hundred yards from the rear of Sickles’ line, or just over half a mile away.Thus, while 15,000 men had departed the area, they had been replaced by almost 11,000 troops. Meade still had 2700 cavalry and 18,000 infantry and artillery in place either holding the line or in immediate reserve. 

    The next major change in dispositions came around Noon. Most significant was the withdrawal of Buford’s cavalry. Buford’s animals were worn out after two weeks of continuous movement prior to the battle, and needed refit time. Buford asked for and got permission to retire from the field to take care of those needs. Major General Alfred H. Pleasanton - Meade’s Cavalry Corps commander - was supposed to replace this force with other troopers, but those replacements never arrived. This proved to be a serious oversight in the overall security of Meade’s left flank. In raw numbers, the arrival of the last division of Fifth Corps added 3300 men to the ranks and offset the manpower loss of Buford’s division, but manpower alone could not replace the screening and early warning potential Buford’s troopers represented. By midday, Sickles had 10,000 of his own men in line, and another 11,000 Fifth Corps troops in reserve directly behind him, but his front was now denuded of cavalry and he was justifiably nervous about that lapse.

    At about 2:00 p.m. Sickles addressed the problem directly. He advanced his whole corps to the new line on Emmitsburg Road, and radically changed the entire defensive scheme. Technically, there were still 21,000 men (his own Third Corps and Fifth Corps) guarding the Union left flank, but now the Third Corps was almost twenty-seven hundred yards in front of the Fifth Corps, well out in front of the rest of the army, and beyond any immediate support in a crisis. Effectively, Sickles’ command would now have to fight the first part of any battle on the left by themselves until the now-distant reserves could come up.

At the start of the day, the Union left started out well manned, and got progressively weaker as the day went on. Between dawn and noon, The Federals always had at least 20,000 men with a strong cavalry presence in place. Even up until about 2:00 p.m., the Federals had 21,000 men in place, though Buford’s departure was a major error. After Sickles advanced, however, the Union line was seriously fragmented: Sickles 10,000 men were remote enough to be beyond immediate help for at least the first 30-45 minutes of any engagement, rendering the placement of 5th Corps moot for at least the opening round of any action. 

    Worst of all, the terrain disadvantages of the forward line all affected Sickles' deployment. Sickles chose to try and cover all thirty-five hundred yards of the new line, and his attempt to refuse the southern end of that line towards the Round Tops placed the awkward angle right at the Peach Orchard, at the apex of converging fire from an entire line of Rebel guns and attacking infantry. 

    These numbers gain additional significance when placed in context with Longstreet’s attacking column. The Confederate First Corps had only two of its three divisions present, for a strength of about 15,500 troops. Lee provided additional support by loaning Anderson’s Division of Hill’s Rebel Third Corps to the attack, for an extra 7000 men, but these troops were not placed to join Longstreet’s attack directly. Instead, Anderson’s men were north of the main attack sector, and would end up engaging other Federals, mostly men from the Union Second Corps, come to support Sickles’ northern flank. Longstreet’s men fought the Union Third and Fifth Corps on their own, sending 15,500 Rebels against 22,000 Federals. When Sickles advanced, he changed that equation dramatically: now Longstreet’s attack would only have to initially confront the 10,000 men of Third Corps, at least until the Federal reserves came up. This shift gave Longstreet an unexpected opportunity: instead of trying to defeat two Federal Corps simultaneously against heavy odds, now he had local superiority against each Corps sequentially.

    Numbers alone do not tell the whole story. Due to abysmal reconnaissance work, Longstreet's attack was aiming at a mythical Union flank. The original concept for the Confederate attack had Longstreet's men deploying across the Emmitsburg Road, facing northeast, towards what the Rebel leadership thought was an exposed Union flank resting about halfway between Cemetery Hill and Little Round Top - in effect the Confederates thought that the Union line ended with the Federal Second Corps. Had Longstreet reached the Peach Orchard unmolested and deployed as intended, his line would have had to advance not towards the Union Third Corps line but instead parallel to it, from south to north. Once he discovered Yankees in the Peach Orchard, however, Longstreet instead deployed his command facing east, and stretching much further south in an effort to find the new Union flank. The result was that Longstreet's line greatly overlapped the Federal force he faced. ^[10]

    Finally, when Sickles did complete the occupation of his advanced line, Third Corps’ problems were compounded by a fatally flawed deployment along that line. As mentioned above, the new position was simply far too long to hold with the manpower Sickles had available. Instead of a single, solid line, the Third Corps instead awkwardly formed into two separate segments, separated in the center by a 400 yard gap covered only by skirmishers and artillery. With only two divisions comprising a total of six brigades, the Third Corps lacked both the raw manpower and the structural integrity to fully man the whole position. Part of Major General David B. Birney’s First Division held the southernmost segment, running from Devils Den through the Rose woods to the Stony Hill. Only two of Birney’s brigades were available to hold this line, and the result was a fragmented mess. Initially, Ward’s brigade held a 400 yard long position facing west, from Devils Den to the south edge of the Wheatfield. De Trobriand’s Brigade was in a similar line about 200 yards further west, in the woods around the Stony Hill and along the west edge of the Wheatfield. Thus, the overall line of these two brigades was about 900 yards long, but because of the staggered deployment, there was a 200 yard gap in the center of Birney’s line. Later, De Trobriand’s men filled in that gap, but in doing so created a battle line with a number of awkward angles. Birney’s remaining brigade, under Graham, held a third segment of the line at the Peach Orchard, leaving another gap, this one of about 400 yards, between it and De Trobriand. Graham's men deployed fronting along the Emmitsburg Road, about 400 yards further west than the rest of Birney's division. Here was the most dangerous gap in the line, hastily filled by five batteries of artillery facing south along the Wheatfield Road. These guns were in a good position to enfilade any attackers moving due east against Birney, but were vulnerable to direct attack without infantry support and would also be exposed if Graham's flank gave way at the Peach Orchard. Overall, Birney's division was deployed over about 1600 yards of ground, with each brigade not in physical contact with its neighbors. 

    The Second Division, under Brigadier General Andrew A. Humphreys, occupied the northern end of the position. Humprheys at least presented a solid front: two of his brigades lined up along the Emmitsburg Road next to Graham, and each connected solidly with the other. This segment of the line (including Graham's men, though technically they were under Birney's command) ran about 1000 yards from just south of the Peach Orchard to a little bit north of the Rogers House. While presenting a solid front to any attack from the west, the left flank had the aforementioned 400 yard gap between it and Birney's line, while the right flank was some 800 yards in advance of the Union Second Corps, back on Cemetery Ridge. Worse yet, Humphreys had to give up one of his brigades to act as Corps reserve, leaving him with an inadequate force to maintain his own sufficient reserves. 

    With only two divisions, the Third Corps was not organizationally well suited to defending this position. In a corps of three divisions, an ideal deployment would be for two divisions to hold the line, while the third division was retained as the Corps reserve. This would allow the Corps commander to hold onto an adequate reserve force, while still giving each of the forward division commanders the option of retaining one of their own brigades as their local reserve. Since the commitment of reserve troops is one of the primary ways any commander can effect a battle in progress, maintaining sufficient reserves is crucial to an effective defense. In the ideal, each commander from brigade level on up would maintain about 1/3 of his force in reserve. Sickles, lacking a third division, was forced instead to adopt a poor substitute: he commandeeredCol. George C. Burling's brigade to act as a corps reserve. Thus, Sickles was forced to make do with only 1/6th of his command as a reserve; and he also robbed Humphreys of any divisionalreserves. This lone brigade would be forced to match the efforts normally expected of a division: Burling's men were ultimately dispatched to points all along the Third Corps line as crises erupted. The monuments to this brigade tell a stark tale: Regimental markers stand along the Emmitsburg Road, in the Peach Orchard, and along Crawford, De Trobriand, and Sickles' Avenues. In each case, they stand not next to units of their own brigade, but alongside regiments of the other five brigades in the corps. Burling, with no brigade left to command, reported: "My command now being taken from me and all separated, no two regiments being together, and being under the command of the different brigade commanders to whom they had reported, I, with my staff, reported to General Humphreys for instructions..." ^[11] Instead of being able to act as a cohesive force, Burling's strength was dissipated in insufficient individual efforts.

    There is some strong evidence that Sickles' advance badly disrupted Meade's overall defensive scheme and significantly degraded Union combat effectiveness. The disruptive effects are easy to see. Union troops sent to help Sickles entered the fight in a fragmented and confusing manner, mirroring on a larger scale the splintering of Burling's Brigade. Further, the large number of troops sent from all corners of the field suggest a reaction more visceral than thought out, as the Confederates overwhelmed formation after formation and Meade sought to stem the tide. Also the losses both sides suffered provide strong evidence of the disparity in the fighting. It is rare that the defender's casualties are higher than the attacker, unless the defense crumbled. In the contest between Longstreet and Sickles, however, the Federal losses were substantially higher than those of the attacking Confederates. 

    The first force rushed to Sickles' support was the Union 5th Corps. Numbering just under 11,000 men in eight brigades, the three divisions of the corps were potentially the decisive edge in any engagement. Unfortunately, this powerful force was never used as a single entity: the trip forward to Sickles' forward position meant the corps arrived piecemeal, and was committed to action that way. the first such diversion occurred when the Corps’ First Division reached the field. Brigadier General Strong Vincent’s Brigade - including the much storied 20th Maine and Col. Joshua Chamberlain - was rushed to Little Round Top to defend that exposed point, since it had become apparent that the Rebel line extended far to the south of the Union position in Devil’s Den and would soon be able to seize the hill. The other two small brigades (commanded by Colonels Tilton and Sweitzer, respectively) were rushed into the Wheatfield. The division was split in half before it ever saw action, and never fought as a unit. The Second Division saw even more fragmentation: one regiment of the Third Brigade was sent up Little Round Top, while the rest of the Brigade was at first sent further north, into the low, swampy ground between the Trostle House and the Wheatfield. Later, the other regiments of Third Brigade joined the line on Little Round Top, but saw almost no action during the battle, their combat power going unused at a crisis point of the fight. The remaining two brigades of this division, both U.S. Regulars,halted first at the northern end of Little Round Top and then charged across Plum Run Valley towards the Wheatfield where they suffered heavily in the fighting there. The Third Division, the famous Pennsylvania Reserves, initially took the place of the Regulars, and later became split as well: one brigade advancing west to cover the retreat of the Second Division while the other brigade moved south behind Little Round Top to support that flank on the other side of the hill.Throughout the entire action, no more than two brigades of the corps fought together in the same fight at any given moment. They were badly intermingled with units of Third and Second Corps, as well as with units of other divisions in their own Corps. 

    The next major reinforcement to arrive was the First Division, Union Second Corps. Numbering four small brigades, it counter-attacked through the Wheatfield after the Third Corps troops (plus Tilton and Sweitzer) had withdrawn from the action, but before the Second Division/Fifth Corps advance from the northern shoulder of Little Round Top. This command, under the leadership of Brigadier General John C. Caldwell, managed to fill the void on Sickles’ left flank after Birney’s line collapsed. 

    Elements of both other Second Corps Divisions became involved in salvaging Sickles’ other flank, after Humphries’ troops were driven from the Emmitsburg Road, flanked both north and south and overwhelmed in the center. Willard’s Brigade/Third Division/Second Corps counter-attacked just east of the Trostle House, while two of Gibbon’s Brigades, Second Division/Second Corps fought a desperate fight east and north of the Klingle House. 

    All told, seven of the Second Corps’ ten brigades became heavily engaged in the battle, and again not as a coherent force. Caldwell’s Division was rushed almost due south on the initiative of General Hancock and spent the afternoon in the Wheatfield. The other brigades were committed once Humphries line was driven in, and became embroiled in various actions along the Emmitsburg Road. 

    Finally, a number of other units ended up backstopping the Federal line, including five brigades of the newly arrived Sixth Corps and three brigades from the Twelfth Corps. None of these eight brigades saw heavy fighting, but some of them skirmished with the last remnants of Longstreet’s attackers. The Twelfth Corps arrivals show the full extent of Meade's scramble to recover. These units were not reserves moved from a rear position, but instead they represented an outright abandonment of part of the main line at Culp's Hill. Had the Confederates been more alert and made a more concerted effort against Meade's right flank, the entire army could have been in grave danger. As it was, a lone Federal brigade managed to withstand a limited Rebel attack on Culp's Hill until enough of the Twelfth Corps could return and seal the breach. 

    Twenty-nine of the fifty-one infantry brigades in the Army of the Potomac were drawn into the fighting along Sickles' sector or sent there in response to the threat, though in some cases they only arrived after the fight was ended. These units amount to approximately 40,850 troops that Meade committed to the engagement. Of those, 20 Brigades can be said to have been heavily involved, suffering 10% or more losses, or 8673 Casualties out of their27,800 men. ^[12]

Weighed against those figures, the Confederate numbers are surprising. Longstreet's command brought eight brigades of the Confederate First Corps to this fight, while Anderson's Division of the Confederate Third Corps contributed three more. ^[13] All told, only eleven Confederate brigades saw any action, numbering 19,900 men, and lost approximately 6350 casualties. ^[14] The Confederates attacked a force that was 50% larger than their own and inflicted 2000 more losses than they suffered, not at all the usual outcome for a Civil War attack. The answer, of course, lies in the nature of the fighting that afternoon. Sickles' forward deployment meant that many of his units were driven back before support was available, and so most of the Federals were not joining an established defensive line, but counter-attacking to re-establish tactical integrity. Moreover, the haphazard nature of the reserves' arrival meant that units had to be flung into action wherever the crisis loomed greatest, destroying a great deal of cohesion for the arriving troops, which in turn meant that the Federals could never really use their greater strength to advantage. Instead of attacking a single, integrated defensive line of 27,000 men, Longstreet's Rebels were able to attack a series of weaker lines, achieving local superiority each time, and then withstand a series of disjointed counter-attacks, each numbering no more than 3-4,000 men. The disparity in losses clearly illustrates the need for tactical cohesion on either defense or offense.