Chantilly

On September 1, 1862, Confederate and Union forces clashed in Fairfax County, Virginia, in an engagement that brought the Northern Virginia Campaign to its close. Southern soldiers referred to this fight as Ox Hill, while it became better known as the Battle of Chantilly. Thomas J. "Stonewall" Jackson led his corps of the Army of Northern Virginia in an effort to block the Union Army of Virginia's path of withdrawal after its defeat at the Second Battle of Bull Run. Two Union divisions responded by striking Jackson's forces before that goal could be achieved. Isaac Stevens and Philip Kearny, both commanding Union divisions, lost their lives amid the fighting that followed, yet their soldiers succeeded in stopping Jackson's advance in its tracks.

Background

After his loss at the Second Battle of Bull Run on August 30, Union Maj. Gen. John Pope commanded his Army of Virginia back toward Centreville. This withdrawal got underway once night had fallen, with Maj. Gen. Irvin McDowell's III Corps serving as a rear guard. Once the army had crossed Bull Run, the final unit to make the crossing, Maj. Gen. Franz Sigel's I Corps, tore down Stone Bridge to prevent pursuit. Gen. Robert E. Lee chose not to capitalize on the momentum from that day's fighting, primarily because his Army of Northern Virginia had grown weary after two straight weeks of near constant marching and roughly three days of combat. As a result, the Federal withdrawal proceeded without interference. This choice by Lee also gave the Army of Virginia's II Corps, commanded by Maj. Gen. Nathaniel P. Banks, the chance to rejoin the main body of Pope's forces as they came in from Bristoe Station, where they had previously been protecting the army's supply trains. Even more significant, Lee's restraint gave the Union time to bring forward the Army of the Potomac's II, V, and VI Corps, units that had been transferred from the Peninsula and, to the great frustration of Maj. Gen. George B. McClellan, placed under Pope's authority.

On the morning of August 31, Pope's grip on his army's command began to slip. The shock of defeat at Second Bull Run appeared to have rattled him badly, leaving him uncertain of his next move. He understood that Washington expected offensive action, yet he worried that Lee could strike first and crush his still recovering force. Pope summoned his corps commanders to a meeting at his Centreville headquarters, a step he had rarely taken earlier in the campaign, and he sided with them in deciding to pull back even further, toward Washington's defensive lines. However, a dispatch from General-in-Chief Henry W. Halleck instructed him to go on the offensive instead, prompting Pope to order an advance against Lee's positions on the Manassas battlefield.

By then, though, Lee had already launched a scheme designed to strip Pope of any chance to attack first. He instructed Maj. Gen. Thomas J. "Stonewall" Jackson to lead his troops around the Union right flank so as to get behind the Federal position at Centreville. Confederate cavalry under Maj. Gen. J.E.B. Stuart rode ahead of Jackson, screening the movement and watching for any force Pope might send to block it. Meanwhile, Maj. Gen. James Longstreet's command stayed put for the day, creating the impression that Lee's whole army remained facing Pope, while Jackson swung north and then east toward the vital crossroads of Germantown, Virginia, where the two roads Pope needed to reach Washington, the Warrenton Pike (today's U.S. Route 29) and the Little River Turnpike (today's U.S. Route 50), came together. Exhausted and hungry, Jackson's soldiers advanced slowly and made camp for the night at Pleasant Valley, some three miles northeast of Centreville. When Pope turned in for the night on August 31, he had no idea that Jackson was close to outflanking him entirely.

During the night, two developments changed Pope's thinking. First, a staff officer rode in from the Germantown area with news that a substantial cavalry force had shelled the crossroads before withdrawing, a threat Pope initially brushed off as nothing more than a patrol. Then, hours afterward, two Union cavalrymen came forward describing a large body of infantry moving east along the Little River Turnpike, and this convinced Pope that his army faced real danger. He reversed his earlier orders to prepare for an attack and instead directed his forces to abandon Centreville and retreat toward Washington. He also dispatched several infantry probes along the roads Lee's troops might use to reach the withdrawing Union columns.

Battle

On September 1, with his cavalry too worn down for scouting duty, Pope told Maj. Gen. Edwin V. Sumner of the II Corps, Army of the Potomac, to push a brigade northward to see what lay ahead. Even as he issued that order, Pope kept shifting his forces toward Washington, dispatching McDowell's corps to Germantown, on the western edge of what is now Fairfax, Virginia, so it could hold the vital junction of Warrenton Pike and Little River Turnpike that the retreating army required. He also detached two brigades of Maj. Gen. Jesse L. Reno's IX Corps, placing them under Brig. Gen. Isaac Stevens, with orders to check Jackson's advance. Maj. Gen. Philip Kearny's division of the III Corps set out to join them later that afternoon.

Meanwhile Jackson pressed southward again, though hunger, exhaustion, and the persistent rain slowed his men to a crawl; they covered a mere three miles before settling on Ox Hill, southeast of Chantilly Plantation, where Jackson himself paused for a nap. Throughout the morning, cavalry from both sides traded skirmishes with infantry. Around three in the afternoon, Stevens' division reached Ox Hill, and though badly outnumbered, he launched an assault across an open, grassy field straight at Brig. Gen. Alexander Lawton's division holding the Confederate center. The Federal push briefly succeeded, scattering the brigade led by Colonel Henry Strong and bending back the flank commanded by Captain William Brown, who lost his life in the struggle. A counterthrust from Brig. Gen. Jubal Early's brigade then threw the Union division back, and it was during this clash, near five o'clock, that Stevens fell, struck by a bullet through the temple.

A violent thunderstorm broke out around this same hour, cutting visibility and forcing soldiers to rely heavily on their bayonets once the downpour ruined their ammunition. Kearny's division arrived to discover Stevens' men in disarray. Spotting an opening in the Union line, Kearny sent Brig. Gen. David B. Birney's brigade to Stevens' left with instructions to charge across the field. Birney pushed his men nearly up to the Confederate position, but the advance bogged down in close combat against Maj. Gen. A.P. Hill's division. During the fighting Kearny accidentally rode into Confederate-held ground and was shot dead. When Kearny's remaining two brigades finally reached the field, Birney used them to cover his withdrawal, pulling the rest of the Union troops back to the southern edge of the farm fields and bringing the battle to its close.

Aftermath

Under cover of darkness, Longstreet moved up to take over from Jackson's exhausted men, planning to resume combat once dawn broke. Opposing forces found themselves positioned so near one another that a number of men wandered by mistake into enemy encampments. As night fell, Union forces pulled back toward Germantown and Fairfax Court House, and in the days that followed they continued retreating until reaching the protective fortifications surrounding Washington. Confederate horsemen tried chasing down the retreating Federals but inflicted little real harm.

The engagement itself settled nothing on a tactical level. Jackson's flanking maneuver had come to nothing, leaving him unable to cut off Pope's withdrawal or crush his army outright. Even so, historians with the National Park Service classify Chantilly as a strategic win for the Confederacy, since it eliminated any remaining threat posed by Pope's forces and opened the door for Lee to launch his campaign into Maryland. Confederates also considered themselves tactical victors, having remained in control of the battlefield once fighting ceased. Casualties among commanders included two Union generals killed and a single Confederate brigade commander lost. Interpreting the assault as a sign that danger to his troops remained real, Pope pressed on with his withdrawal into the defensive works ringing the capital. With Pope's forces gone from Virginia, Lee launched his push into Maryland, a campaign that would eventually reach its climax at Antietam. Meanwhile, Maj. Gen. George B. McClellan's Army of the Potomac took in the soldiers of Pope's Army of Virginia, which ceased to exist as its own independent command.