The Battle of Blackburn's Ford was fought on 18 July 1861 during the American Civil War.
On 16 July 1861, the 35,000-strong Union Army of the Potomac under Irvin McDowell marched south from Washington DC to give battle to the Confederate Army of Northern Virginia at the Manassas railroad junction. The army reached Fairfax Court House on 17 July, and he sent Brigadier-General Daniel Tyler to look for a fording point across Bull Run Creek. On 18 July, Tyler entered Centerville and then marched southeast to Blackburn's Ford, where he failed to notice James Longstreet's brigade concealed in the woods. He ordered Romeyn B. Ayres' howitzers to bombard the Confederates he could see, and he then sent Israel B. Richardson's brigade forward. Richardson's assault failed under heavy fire, causing a wave of panic throughout the Union line. Jubal Early then arrived with Confederate reinforcements, and the Union forces withdrew in the face of superior firepower. The Union troops withdrew under an artillery bombardment, and the failure of the reconnaissance-in-force at Blackburn's Ford led to McDowell deciding on a frontal assault on the Confederate army in the First Battle of Bull Run.