On 16 July, 1861, the untried Union army under Brigadier General Irvin McDowell, 35,000 strong, marched out of the Washington defenses to give battle to the Confederate army, which was concentrated around the vital railroad junction at Manassas
The Confederate army, about 22,000 men, under the command of Brigadier General P.G.T. Beauregard, guarded the fords of Bull Run.
On July 18, McDowell reached Centreville and pushed southwest, attempting to cross at Blackburn's Ford. He was repulsed.
This action was a reconnaissance-in-force prior to the main event at Manassas / Bull Run.
Because of this action, Union commander McDowell decided on the flanking maneuver he employed at First Manassas.
Result(s): Confederate victory
Location: Prince William County and Fairfax County
Campaign: Manassas Campaign (July 1861) next battle in campaign previous battle in campaign
Date(s): July 18, 1861
Principal Commanders: Brigadier General Irvin McDowell [US]; Brigadier General P.G.T. Beauregard [CS]
Forces Engaged: Brigades
Estimated Casualties: 151 total (US 83; CS 68)