The fighting at Ox Hill occurred during a fierce storm that field reports described as so thunderous it drowned out the cries and clamor of the battle. Dry ammunition became scarce, and the fighting degenerated into a brawl of bayonets and musket clubs. The chaotic conflict lasted a little more than two hours and ended at dark as a stalemate. The park that commemorates this battle is the one of the best interpreted sites in Fairfax County's Civil War sites inventory.
The events at Ox Hill were triggered by Confederate General Robert E. Lee's attempt to outflank the retreating Union army. After the battle of Second Manassas along Bull Run on August 28-30, 1862, the Federal Army retreated toward the well-protected capital city of Washington.
Two Union divisions under the command of General Isaac Stevens and Major General Philip Kearny engaged Confederate troops at Ox Hill on September 1. Both Stevens and Kearny were killed.
Historians differ in their estimates of the troops involved. Some 4,000 to 6,000 Union troops were in the area, and about 15,000 to 17,000 Confederate troops were nearby. Historians think at least 1,000 Union troops died or were injured. The Confederates counted 516 casualties.
Ox Hill marked the end of the Second Manassas Campaign. After the engagement, the Federal Army completed its retreat to the fortifications around Washington. The Confederates turned north and crossed the Potomac River, igniting the Maryland Campaign. Sixteen days after Ox Hill, the armies met near Antietam Creek in Sharpsburg, MD and engaged in the bloodiest single day of the war.
Ox Hill/Chantilly battle description courtesy Fairfax County Park Authority