Early Organization and Administration
On the day he reached Washington, McClellan began to turn McDowell's raw and undisciplined troops—most of whom hailed from New England and the Middle Atlantic states—into soldiers. The men were efficiently organized, thoroughly trained, and well armed and equipped. Morale rose and the troops came to regard the handsome, nattily attired, and splendidly mounted "Little Mac" as their savior. McClellan's popularity with the rank-and-file would endure long after his removal from command late in the autumn of 1862. From the start, he was less popular among his political superiors; for months he ignored Lincoln's urgings—and then his demands—that the effective army McClellan had created take the offensive.
Originally, the army's highest echelon was the division, on paper consisting of approximately 12,000 men. Early in March, the command having swollen to more than 125,000 men, Lincoln ordered McClellan to create four corps (later expanded to six), each composed of two or three infantry divisions, with artillery and cavalry attached. During the Peninsula Campaign, these units were commanded, respectively, by major generals McDowell, Edwin V. Sumner, Samuel P. Heintzelman, Erasmus D. Keyes, Fitz-John Porter, and William B. Franklin. As would later become evident, each officer owed his position to seniority, not tactical prowess.
Command of the army's field artillery, which by early 1862 consisted of some 100 six-gun batteries, went to Brigadier General William F. Barry, who was a better administrator than a combat leader. Barry's second-in-command, Colonel Henry J. Hunt, supervised the army's 100-cannon artillery reserve. In September 1862, Barry was succeeded by Hunt, who served as chief of artillery for the rest of the war. Although never accorded rank commensurate with his vast responsibilities, Hunt gained a reputation as the most talented artillerist in the nineteenth-century American army. Confederate commanders conceded the superiority of his command, which remained a constant throughout the war.
McClellan's handling of the army's cavalry and his selection of its commander lacked inspiration. By reducing his mounted arm—initially 6,500 troopers—into small units for tactical employment, he frittered away its latent power. Titular command reposed in Brigadier General George Stoneman, who rarely had more than a few hundred troopers at his disposal. Ultimate authority was vested in the commanders of the corps to which the mounted units were attached, few of whom had cavalry experience.
For the first two years of the war the army's horsemen—relatively few of whom were native equestrians—were overmatched by Lee's cavalry under Major General J. E. B. Stuart. Not until mid-1863, when organized into an independent corps, was the cavalry able to compete against its vaunted adversary. By then the command had grown to 11,000 and had acquired such capable leaders as Brigadier Generals John Buford, David McMurtrie Gregg, Wesley Merritt, and George A. Custer. On the eve of the war's final year, command of the corps passed to Major General Philip H. Sheridan, whose hard-driving leadership helped it gain a sustained advantage over its adversary.
To head the army's many support units, McClellan selected well. As quartermaster general of the army he appointed Brigadier General Stewart Van Vliet, assisted and later succeeded by the resourceful Brigadier General Rufus Ingalls. Other efficient staff officers included the army's chief engineer, Brigadier General John G. Barnard; its chief topographical engineer, Brigadier General Andrew A. Humphreys (later a major general and corps commander); its chief commissary, Colonel Henry F. Clarke; its provost marshal, Brigadier General Marsena R. Patrick; and its adjutant general, Brigadier General Seth Williams. Most of these officers retained their positions under McClellan's many successors.
Although a gifted organizer and morale builder, McClellan proved a failure as a field commander. In early April 1862 Little Mac, having shipped his troops in transports to Fort Monroe, led them up the Virginia Peninsula to Yorktown. There he confronted a small garrison whose strength he greatly overestimated. Surprised and cowed, he spent a month laying siege to the port village. On May 3, just as his laboriously erected siege batteries prepared to open fire, the Confederates evacuated, heading for Richmond.
McClellan launched a ponderous pursuit, slowed further by a delaying action at Williamsburg. By late May most of his army was finally in position to attack or invest the enemy capital, but his ranking opponent, Joseph E. Johnston, struck first, precipitating the Battle of Seven Pines–Fair Oaks, May 31–June 1. Although the fighting ended with Johnston's withdrawal, it had exposed McClellan's faulty dispositions astride the Chickahominy River. Robert E. Lee, who replaced the wounded Johnston on June 1, was quick to take advantage. A raid by Stuart around the rear of the Army of the Potomac, weakly opposed by the fragmented and scattered Union cavalry, gave Lee the information he needed to launch a week-long series of attacks aimed at pushing his opponent as far from Richmond as possible. Almost all of the subsequent Seven Days' Battles ended in a draw or a tactical victory for the Army of the Potomac, which nevertheless retreated at McClellan's order. When the last Confederate assault was repulsed at Malvern Hill on July 1, thanks largely to the devastating power of Hunt's cannons, the flustered and intimidated McClellan was ensconced at Harrison's Landing on the James River, twenty miles from his unattained objective.
Although he had outnumbered Lee handily, McClellan accused the Lincoln administration of failing to provide him with sufficient manpower. After Malvern Hill he refused to reassume the offensive unless reinforced to an exorbitant extent. Unwilling to comply, Lincoln's newly assigned general-in-chief, Henry W. Halleck, ordered that most of the army return to Washington, D.C. The Third and Fifth corps and elements of two other corps were hastened west, where Major General John Pope's Army of Virginia was engaging the vanguard of Lee's army under Major General Thomas J. "Stonewall" Jackson near Culpeper Court House. The two Union armies failed to mesh, helping to bring about Pope's decisive defeat on August 29–30 on the fringes of the old Manassas battlefield. The botched campaign ended with a general withdrawal to Washington and in Pope's relief. Fitz-John Porter, a political rival of Pope's, became a scapegoat for the debacle; subsequently court-martialed, he was dismissed from the service for alleged disobedience of orders. Meanwhile, Pope's survivors were absorbed into the Army of the Potomac, which McClellan continued to lead.
Lee, flushed with victory, led the Army of Northern Virginia across the Potomac River into Maryland. Obliged to pursue, McClellan moved at his customary glacial pace. In mid-September he finally caught up with his opponent along Antietam Creek. The battle fought there on September 17, 1862, the bloodiest day in American history, inflicted 12,400 Union and more than 13,000 Confederate casualties. Lee's precarious position, McClellan's strength advantage and his capture of a copy of Lee's invasion plan should have produced a clear-cut Union victory. But Little Mac squandered his advantage through disjointed assaults, and he failed to ensure that subordinates performed capably. The primary underachiever, Major General Ambrose E. Burnside, commander of the newly acquired Ninth Corps, spent several hours trying to cross the creek in the face of a much smaller enemy and turn the Confederate right. When finally across, Burnside was stymied by late-arriving reinforcements.
The Army of the Potomac gained a strategic victory when, late on September 18, Lee ended his invasion and returned to Virginia. As though content to let him go, for six weeks McClellan remained in Maryland, resting and reorganizing. When Lincoln visited the stationary army, he described it as "McClellan's bodyguard." On November 7, political pressure forced him to relieve the general. To replace him, Lincoln unwisely chose Burnside, a soldier known more for stubbornness and inflexibility than for proficiency in combat.
Lincoln was encouraged when Burnside developed a seemingly viable plan to outflank Lee on the road to Richmond by crossing the bridgeless Rappahannock River opposite Fredericksburg. Burnside's army—which now consisted of eight corps divided into four "Grand Divisions"—stole a march on its enemy, but errant pontoon trains stranded it on the north bank near Falmouth. Before the bridges arrived, Lee took up nearly impenetrable positions south and west of Fredericksburg. Refusing to reconsider his strategy, on the frigid morning of December 13 Burnside commenced a series of gallant but doomed assaults, many directed toward a well-defended stone wall at the base of Marye's Heights. Although the Union troops briefly gained a foothold along Lee's right, by day's end 13,000 had been killed or wounded compared to fewer than 5,500 Confederates.
Chancellorsville and Gettysburg, 1863
Late in January 1863 Burnside tried to salvage his campaign via a turning movement beyond Lee's western flank. Soon after the army got underway, rain, snow, and impassable roads brought an ignominious end to the "Mud March." On January 26, finally convinced of Burnside's incapacity and influenced by the intriguing of some of his subordinates, Lincoln replaced him with Major General Joseph Hooker. A caustic but relatively discreet critic of his deposed superior, "Fighting Joe" overflowed with self-confidence bordering on hubris; he once boasted that "God Almighty could not prevent" him from besting Lee. For all his faults, however, Hooker was a talented organizer and motivator. By dismantling the unwieldy Grand Division structure and consolidating his cavalry, he made the army more mobile and powerful. By ensuring that the men were better fed, supplied, and armed, he won their gratitude and respect. And by holding regular reviews and issuing corps badges, he bolstered morale and unit pride.
Like his predecessor, Hooker devised a complicated but promising plan to turn Lee out of his defenses below Fredericksburg. Late in April he led about one third of his 134,000-man army across the Rappahannock and into the rear of the Army of Northern Virginia. Another third was held in reserve; the rest remained near Falmouth to divert Lee's attention. Hooker's advance achieved surprise, but once across the river he made faulty dispositions, trapping his troops inside the dark and clotted Virginia Wilderness. More critically, at the eleventh hour he displayed moral infirmity—with success seemingly within his grasp, he went over to the defensive. At last aware of the danger to the rear, Lee turned about and attacked from two directions. The crucial blow was delivered on May 2 by 26,000 troops under Jackson who demolished Hooker's unanchored right flank near the Chancellorsville crossroads. Four days of ferocious but confused fighting ended when Hooker, thoroughly demoralized and dazed by a shell burst, withdrew the army to Falmouth.
In the aftermath of its latest humiliation, the Army of the Potomac marked time on the Rappahannock even as Lee completed plans for his second invasion. He began moving west and north on June 3, heading for Maryland via the Shenandoah Valley. Thanks partially to reconnaissance lapses by the Union cavalry, now led by Brigadier General Alfred Pleasonton, Hooker did not discover his opponent's departure until mid-month. Only after the president vetoed Hooker's proposal to advance on Richmond (a move Lincoln and Halleck feared would uncover Washington), did the Army of the Potomac move north in strength. For two weeks, however, it remained in northern Virginia while the Confederates pushed into Pennsylvania.
Sensing that he had lost the confidence of his superiors, Hooker forced a showdown by demanding that the garrison of Harpers Ferry, Virginia, be added to his field force. When Halleck refused, Hooker tendered his resignation, which was quickly accepted. To replace him Lincoln selected the commander of the army's Fifth Corps, Major General George G. Meade, a competent but prickly soldier who could be counted on to defend his home state of Pennsylvania. With mixed emotions, Meade assumed command on June 28, three days before his advance overtook Lee's army outside Gettysburg and brought on one of the war's pivotal battles.
On July 1, during the first day of fighting at Gettysburg, Lee's vanguard—a full division of infantry—was held at bay by John Buford's outnumbered but tenacious cavalry. In classic dragoon tradition, Buford's troopers (who had first distinguished themselves in battle against J. E. B. Stuart the previous month at Brandy Station) fought in the saddle and afoot, as conditions dictated. The delaying action enabled the lead elements of the army's advance wing, under the able Major General John F. Reynolds, to reach the field. Overwhelmed by faster-arriving Confederate reinforcements and demoralized by the mortal wounding of Reynolds, late in the afternoon cavalry and infantry withdrew through Gettysburg. On high ground south of town they withstood further pressure until nightfall ended the fighting.
On July 2, the Army of the Potomac, now on the field in full strength, turned back offensives against both of its flanks. It gained an especially critical victory on the far left, where a desperate defensive effort secured strategic Little Round Top. On the third, Hunt's artillery helped break up a climactic assault by 12,500 Confederates (Pickett's Charge) against the center of the Union line along Cemetery Ridge. While infantrymen and artillerists grappled, cavalry under Gregg and Custer repulsed an attempt by Stuart to break through in the far rear. The battle—which claimed 23,000 Union and 28,000 Confederate casualties came to be known as the High Water Mark of the Confederacy. Afterward, the tide of Confederate victory began to recede.
When Meade failed to attack on July 4, Lee pulled out and headed for Maryland. The next day, his opponent began a cautious pursuit. Small-unit skirmishes—mostly cavalry affairs—consumed the next ten days. But although the rain-swollen Potomac prevented the Army of Northern Virginia from returning to its namesake region until July 13–14, Meade failed to deliver a parting blow. When Lincoln bemoaned the loss of a precious opportunity to destroy Lee's command, the prideful Meade offered his resignation but eventually consented to stay on. He would lead the army through the balance of the war.
The Coming of Ulysses S. Grant, 1864
Autumn 1863 was a season of maneuvering by both armies in the disputed area between the Rappahannock and Rapidan rivers. It featured relatively few large engagements, mainly because both commanders, sensitive to recent manpower losses (Meade's Eleventh and Twelfth corps had been transferred to Tennessee to help Ulysses S. Grant lift the siege of Chattanooga), avoided a major confrontation. The largest clash occurred in mid-October when the crack Second Corps broke up a Confederate assault at Bristoe Station on the Orange and Alexandria Railroad. In late November a promising drive below the Rapidan against Lee's right flank was blocked along Mine Run. Small-unit actions closed out the winter, capped by a raid on Richmond (February 28–March 4) by cavalry under Brigadier General Judson Kilpatrick and Colonel Ulric Dahlgren. Controversy surrounded the expedition, which ended in Kilpatrick's retreat, Dahlgren's death, and the discovery of papers on the colonel's body suggesting the raiders had intended to capture and kill Confederate officials, including Confederate president Jefferson Davis.
Believing that Meade needed help to defeat Lee and take Richmond, Lincoln called Grant to Washington. On March 9, 1864, the victor at Shiloh (1862), Vicksburg (1863), and Chattanooga (1863) accepted promotion to lieutenant general, thus replacing Halleck in overall command of the Union armies. Recognizing the critical importance of the war in Virginia, especially with Lincoln up for reelection in November, Grant chose to make his headquarters with the Army of the Potomac. He would give the army strategic direction while allowing Meade to handle tactical dispositions and conduct combat operations The unorthodox arrangement appeared fraught with friction and discord, but the two generals managed to develop a mutual trust and admiration that made the relationship work.
From the Wilderness to Petersburg, 1864
Grant's so-called Overland Campaign—in effect, a continuous and nearly year-long advance—began on May 4, 1864. That morning Meade's army, which due to battle losses had been consolidated into the Second, Fifth, Sixth, and Ninth corps, crossed the Rapidan east of Lee's headquarters at Orange Court House and plunged into the Wilderness. Next morning, before Union troops cleared the forest, Lee rushed up and brought them to a halt. For two days the armies clashed furiously and often blindly in the woodland where Hooker and his men had met disaster just one year earlier. By the close of the day on June 6, the Army of the Potomac had absorbed 17,000 losses (some 15 percent of its total strength) to little avail—the road to Richmond had been effectively blocked.
Unlike Meade's predecessors, Grant refused to retreat and salve his wounds. Late on the seventh the Army of the Potomac shifted southeastward and resumed its advance. Enjoying interior lines of movement, Lee barred Meade's path near Spotsylvania Court House, precipitating a series of bloody but indecisive battles (May 8–21). During this period Meade's newly installed cavalry leader, Philip H. Sheridan, led 10,000 horsemen on a raid in the general direction of Richmond. Again the Confederate capital escaped capture, but on May 11, at Yellow Tavern, Sheridan battled Stuart's cavalry to a standstill and mortally wounded its celebrated commander.
On May 21 Grant had the army disengage and march to the North Anna River, where he was again stymied by the alert Lee. By the close of May Meade's army was heading to Cold Harbor, a crossroads hamlet ten miles northeast of Richmond. Once again Lee got there first and dug in. Backed up against the James River, a frustrated Grant ordered Meade's troops and an attached column from Major General Benjamin F. Butler's smaller Army of the James to attack Lee's hastily constructed but formidable defenses. The assaults of June 1 and 3 produced drastic losses, bringing Union casualties to a total of 50,000 since the start of the campaign.
Obliged to plan anew, on June 12 Grant sent Butler's forces by transport down the Pamunkey and York rivers and then overland to Petersburg, twenty-two miles below Richmond. As Butler moved out, Meade's troops began to cross the James on pontoons. On the south side they, too, headed for Petersburg, Richmond's primary supply center. The risky stratagem was aided by diversions, including a raid by Sheridan toward Charlottesville. The expedition culminated in the war's largest mounted battle, at Trevilian Station (June 11–12), where Sheridan was roughly handled and turned back.
At first, Grant's plan to take Petersburg appeared a brilliant success. The Army of the James reached its lightly defended objective before Lee realized it had left Cold Harbor. Then, however, a disastrous lack of cooperation between Butler's advance and the later arrivals under Meade produced a series of uncoordinated, piecemeal attacks that were soundly repulsed. By June 18, having discovered Grant's escape, Lee was at Petersburg with his entire army.
Unwilling to concede defeat, Grant sanctioned a fantastic-sounding scheme to dig a powder-filled mine under an enemy salient on the east side of Petersburg. On July 30 the mine detonated, blowing the salient to pieces, but a botched attack (the Battle of the Crater) ended any chance of taking the city by storm. Grant now felt compelled to besiege both Petersburg and Richmond. Over time the operation, shared by Meade's and Butler's armies, forced Lee to extend his lines more than thirty miles. Though ultimately successful, the time-consuming strategy lowered the morale of the Northern public, causing Lincoln to despair of reelection.
In mid-July, Grant was forced to detach troops to repulse a raid on Washington by Lieutenant General Jubal A. Early. On August 1 he sent Sheridan, with the Sixth Corps and two of Meade's cavalry divisions, to the Shenandoah Valley, to which the raiders had withdrawn. Sheridan spent the next seven months battling Early and laying waste to the "Breadbasket of the Confederacy." A series of dramatic victories over the Valley Confederates, combined with the September 2 capture of Atlanta, Georgia, by Major General William T. Sherman (Grant's successor in the West), revived spirits throughout the North and helped Lincoln defeat his Democratic opponent, former General McClellan, who had run on a peace platform.
The Road to Appomattox, 1865
Into the spring of 1865 the Army of the Potomac continued to extend its lines below Petersburg. On March 29 it began a final effort to crush Lee's right flank. On April 1 infantry and cavalry under Sheridan, recently returned from the Valley, achieved a breakthrough at Five Forks. The next day Lee evacuated Petersburg, Richmond, and the works in between. His army headed west, hoping to turn south and link with Joe Johnston's army in North Carolina. By hard marching, elements of the Army of the Potomac forged ahead of the weary, half-starved Confederates and brought them to a halt near Appomattox Court House. Failing to clear the roadblock, Lee surrendered to Grant on April 9. Lee's capitulation had a demoralizing effect on other Confederate forces, including Johnston's, which surrendered to Sherman on April 26.
The Army of the Potomac endured some of the most devastating and humiliating defeats in the history of American arms, yet it never relinquished its quest for ultimate victory. By prevailing over a formidable foe despite political pressure and both uninspired and incompetent leadership, the army came to epitomize tenacity and perseverance. Its long-suffering troops fervently hoped that history would grant them these accolades. As one of its enlisted men observed midway through the war, "It is actually wonderful how the Army of the Potomac stand the deprivations, trials, & reverses that have been heaped on them without stint or mercy to meet the foe with undaunted spirits. … I look forward to the time when a man can say with pride, 'I belonged to the Army of the Potomac'." That day finally came on April 9, 1865.
July 25, 1861 - The Military District of the Potomac is formed; it comprises troops from the Army of Northeastern Virginia and the defenses of Washington.
August 15, 1861 - Upon the merger of the military district into the Department of the Potomac, its army assumes the name it will bear for the remainder of the war.
August 20, 1861 - George B. McClellan forms the Army of the Potomac out of Union troops gathered in Washington, D.C. He becomes its first, best-loved, and most controversial commander.
April–May 1862 - In the Peninsula Campaign, Union general George B. McClellan leads the Army of the Potomac toward the Confederate capital at Richmond from the southeast.
May 31–June 1, 1862 - In the Battle of Seven Pines, Confederate general Joseph E. Johnston takes advantage of a flooding Chickahominy River and attacks a split Union army under George B. McClellan. Only stubborn fighting and timely reinforcements save McClellan from disaster. Johnston is severely wounded in the fighting.
June 25–July 1, 1862 - In the Seven Days' Battles near Richmond, Robert E. Lee defeats George B. McClellan in a series of fierce engagements. In contrast to the Shenandoah Valley campaign, Confederate general Thomas J. "Stonewall" Jackson's movements are slow, sparking controversy among contemporaries and subsequent historians over the reasons for Jackson's performance.
August 1862 - After defeat in the Seven Days' Battles, Union general George B. McClellan is ordered back to Washington, D.C., and most of his troops are transferred to a new army under John Pope.
August 28–30, 1862 - At the Second Battle of Manassas, Robert E. Lee's Army of Northern Virginia defeats Union forces under John Pope.
September 17, 1862 - In the bloodiest single day of the war, George B. McClellan attacks Confederates under Robert E. Lee at Antietam Creek in Maryland. The battle ends in a stalemate, but Lee is forced to retreat south to Virginia.
December 13, 1862 - Confederate general Robert E. Lee and the Army of Northern Virginia crush Union general Ambrose E. Burnside and the Army of the Potomac at the Battle of Fredericksburg in one of the most lopsided defeats of the war.
May 1–4, 1863 - Joseph Hooker is defeated by Confederate generals Robert E. Lee and Thomas J. "Stonewall" Jackson at the Battle of Chancellorsville.
July 1–3, 1863 - Union general George G. Meade defeats Robert E. Lee at the Battle of Gettysburg, forcing the Confederate Army of Northern Virginia to retreat toward Virginia.
March 10, 1864 - Ulysses S. Grant is promoted to lieutenant general and named general-in-chief of all United States armies.
May 5–June 3, 1864 - Ulysses S. Grant, the Union's new general-in-chief, directs the Army of the Potomac south toward Richmond. Bloody and largely inconclusive fights at the Wilderness and Spotsylvania, along the North Anna River, and at Cold Harbor result in Grant's army's taking up siege positions before Petersburg.
June 15, 1864–April 2, 1865 - Ulysses S. Grant presides over the Petersburg Campaign and effects the evacuation of Richmond and Petersburg.
July 30, 1864 - The Battle of the Crater causes 4,000 Union casualties and, though a technical success, is a tactical catastrophe for Ulysses S. Grant.
April 6, 1865 - At the Battle of Sailor's Creek during the Appomattox Campaign, Confederate general Robert E. Lee loses 20 percent of his army, most of it captured, including nine generals.
April 9, 1865 - Confederate general Robert E. Lee and the Army of Northern Virginia surrender to Union general Ulysses S. Grant at Appomattox Court House.
- Civil War, American (1861–1865)
Cite This Entry
- APA Citation:
Longacre, E. Army of the Potomac. (2012, April 19). In Encyclopedia Virginia. Retrieved from http://www.EncyclopediaVirginia.org/Army_of_the_Potomac.
- MLA Citation:
Longacre, Edward. "Army of the Potomac." Encyclopedia Virginia. Virginia Foundation for the Humanities, 19 Apr. 2012. Web. READ_DATE.
First published: January 25, 2012 | Last modified: April 19, 2012
Contributed by Edward Longacre, a retired historian for the Department of Defense. The author of biographies of several Union and Confederate generals, he lives in Newport News.