Disunion follows the Civil War as it unfolded.
After months of preparation by both the Union and Confederate governments, more than 80,000 soldiers held strategic positions across northern Virginia during the first weeks of July 1861. The largest army ever fielded by the United States, 35,000 strong and commanded by Brig. Gen. Irvin McDowell, occupied the area around Arlington and Alexandria, just across the Potomac River from Washington (see Map 1). A second Union force of 18,000 men, led by Brig. Gen. Robert Patterson, guarded the lower Shenandoah Valley, near Harpers Ferry.
Two Confederate forces confronted their Union opponents: Brig. Gen. G. T. Beauregard, the “Hero of Sumter,” held Manassas Junction with 20,000 men, while Brig. Gen. Gen. Joseph E. Johnston stood near Winchester, a few miles southwest of Patterson’s position, with another 12,000 troops. Though the Union had the advantage of greater numbers, the Confederate forces enjoyed what military officers called interior lines: this meant that Johnston, by making use of the Manassas Gap Railroad, could reinforce Beauregard more quickly than Patterson could move to join McDowell.
Increasing clamor for military action in both the United States and the Confederacy had been building since the firing on Fort Sumter in mid-April, and Virginia’s secession and transfer of the Confederate capital from Montgomery, Ala., to Richmond had focused attention and planning on the Potomac frontier. Key members of the Union high command, including General in Chief Winfield Scott and McDowell, initially recommended against precipitate action, noting that newly raised volunteers were ill-prepared for the harsh reality of combat. Political pressure and public opinion won out, however, and Abraham Lincoln determined that an early victory might convince the Confederate people to give up their experiment in rebellion.
McDowell marched westward toward Beauregard’s army on July 16. He expected Patterson to pin Johnston down in the Valley, thereby denying the rebels a chance to combine their forces. But, as he and Scott had predicted, the men were not ready for such a grueling trek, and they made very slow progress, finally reaching Centreville, about 20 miles away, before noon on July 18.
By that time Beauregard, well informed about McDowell’s plodding advance, had placed his units in a defensive position covering key fords and bridges across Bull Run, a creek a few miles west of Centreville. Preliminary skirmishing at Blackburn’s Ford and Mitchell’s Ford that afternoon yielded a Confederate success and prompted McDowell to pull back and consider his options (see Map 2). The Confederate right flank seemed secure, so he plotted a movement around Beauregard’s left — a classic military tactic called “turning the flank” — in the vicinity of Stone Bridge on the Warrenton Turnpike. Unknown to the Federal commander, Patterson had failed in his mission in the valley, and Johnston had begun to shift his brigades to the railroad that would take them on to Manassas Junction.
McDowell failed to engage the rebels again until the morning of July 21. The intervening three days afforded time for most of Johnston’s troops to arrive by rail to reinforce their comrades posted along Bull Run (see Map 3). Still, the initial stage of the battle favored McDowell and his superior numbers. More than 10,000 federal troops crossed Bull Run at Sudley Ford, while others feinted against Confederates at Stone Bridge. Sharp fighting north of the Warrenton Turnpike on Matthew’s Hill and Buck Hill slowed the Union advance, but the rebels, ably led by Brig. Gen. Nathan G. Evans, retreated in some disorder across the turnpike. Beauregard and Johnston abandoned thoughts of turning McDowell’s left flank and redeployed units to buttress their own crumbling left.
The early afternoon’s action concentrated on Henry Hill, a substantial plateau that rose abruptly from Young’s Branch along the Turnpike. Confederates from the morning’s fighting rallied on the high ground as other regiments came to their support against the Union attackers (see Map 4). At a critical juncture, a South Carolina brigadier sought to inspire some of his troops, who had been scattered in earlier action, to re-enter the fight. Pointing toward the five Virginia regiments of Brig. Gen. Thomas J. Jackson’s brigade, Barnard E. Bee shouted: “Yonder stands Jackson like a stone wall; let’s go to his assistance!”
Although Bee’s effort did not trigger a decisive change in momentum, more than two hours of sustained combat on Henry Hill finally swung against the federal troops as Confederate reinforcements applied increasing pressure. Shortly after four o’clock, a number of Union brigades, including those led by future army commanders William Tecumseh Sherman and Oliver Otis Howard, withdrew toward Sudley Ford and Stone Bridge (see Map 5).
A crisis for the Federal forces had arrived; raising the Rebel Yell for the one of the first times in the war, Confederates built momentum until they forced their enemy into full retreat. Picnicking civilians who had driven out from Washington to witness a Union victory found themselves swept up in a fleeing mass of soldiers, pieces of artillery, supply wagons and carriages that choked the Warrenton Turnpike. Representative Alfred Ely of New York, captured during the chaotic aftermath of the battle and treated roughly by a hot-tempered Confederate colonel, found himself en route to Richmond and confinement in Libby Prison.
Still, things could have been worse for the Union; the Confederates could have pressed on to the Potomac. But they were nearly as disorganized in victory as their foe was in defeat, and they failed to mount a pursuit that could prevent McDowell’s demoralized army from reaching the safety of Washington.
The First Battle of Bull Run gave citizens in both the Confederacy and the United States a small taste of the carnage to come over the next four years. Though the casualty counts paled in comparison to those at Antietam or Gettysburg, they exceeded those of any previous battle in the American history: out of the of the approximately 18,000 men on each side who got into action, nearly 3,000 federal and 2,000 Confederate soldiers were killed, wounded or taken prisoner. Morale soared across the Confederacy, while the loyal citizenry of the United States braced for a longer and harder war than most could have imagined.
Gary Gallagher is a professor of history at the University of Virginia and the author of, most recently, “The Union War.”