Brigadier General Irvin McDowell was appointed to command the Army of Northeastern Virginia, by President Abraham Lincoln. He was prodded to attack by the Washington politicians, who wanted a quick victory to solidify their standing. Although McDowell did not want to attack, stating that his forces were green, he eventually was forced to.
McDowell's plan was to use Brig. Gen. Daniel Tyler's division to feint an attack on Stone Bridge, which went across Bull Run, while Colonel Thomas A. Davies's brigade would feint at Blackburn's Ford. However, his main attack would be by Brig. Gens. David Hunter and Samuel P. Heintzelman, who would flank the Confederate troops at their left flank (the Union's right). This was a sound plan; however, McDowell's forces were much too green to carry it out effectively.
On the other hand, the Confederate troops were in some disorder. Commanded overall by Brig. Gen. P.G.T. Beauregard (the hero of Fort Sumter), their order of battle was rather unwieldy, with about 1/3 of their troops forced marching from the Shenandoah Valley. However, a small brigade under Colonel Nathan Evans stood in the Union path. Had this unit faltered, or not been present, the flank attack would have succeeded. However, these few men were able to hold until the entire Federal army attacked, after which the Confederate units retreated.
However, a group of Virginia soldiers commanded by Brig. Gen. Thomas J. Jackson, refused to lose ground. Fellow Confederate officer, Brig. Gen. Barnard Bee said, "Look! There is Jackson standing like a stone wall! Rally behind the Virginians!" The Confederates did just that, and the battle resulted in a humiliating rout of Union forces and a disorderly retreat, bringing the battle to a halt. In addition, General Jackson became known as "Stonewall Jackson."
General Jackson's arrival meant that the Army of the Shenandoah, under Brig. Gen. Joseph Johnston had arrived, and this force, along with Beauregard's Army of the Potomac, attacked. The Federal right flank, which was in disorder because of the halted attack, was routed, driven back, and eventually, in full flight.
The elite of nearby Washington, DC, expecting an easy Union victory, had come out to watch the battle and picnic. When the Union Army was driven back, the roads back to Washington were blocked by panicked civilians attempting to flee in their carriages. Further confusion ensued when an artillery shell fell on a carriage, blocking the main road north. Although the Confederates would probably have won the war had they marched on Washington during the rout, they were too exhausted to follow through with a pursuit of the enemy.
Casualties totaled approximately 3,000 - 5,000 Union troops and 2,000 Confederates.
See also: Second Battle of Bull Run