The war erupts on a large scale in the east when Confederate forces under P. T. Beauregard turn back Union General Irvin McDowell's troops along the Bull Run stream in Virginia. The inexperienced soldiers on both sides slugged it out in a chaotic battle that resulted in a humiliating retreat by the Yankees and signaled, for many, the true start of the war.
At the insistence of President Abraham Lincoln, McDowell set out to make a quick offensive against Manassas Junction, a key rail center 30 miles from Washington, D.C. On July 18, the Yankee advance was halted in a small skirmish at Blackburn's Ford on Bull Run. McDowell paused for three days as he prepared to move around the Rebels. This was a crucial delay, because it allowed forces under Joseph Johnston, guarding the Shenandoah Valley to the west, to join Beauregard. A brigade commanded by Thomas J. Jackson was among the reinforcements.
When McDowell attacked on July 21, the Federal troops seemed poised to scatter the Confederates in front of them. While part of the Union force held the attention of the center of the Confederate line, the main attack came around the Rebel left flank. By noon, the Yankees had broken the line and sent the Confederates in retreat. Then McDowell moved in for the kill by attempting to capture Henry Hill, the key to the battle. But he did not apply the full pressure of his army, and that respite allowed Beauregard to strengthen his force on the hill. Jackson's brigade moved artillery into place, and McDowell now faced a much stronger Confederate position.
During the battle, General Barnard Bee led his Confederates to reinforce Jackson on Henry Hill. He was reported to have characterized Jackson as "standing like a stone wall." Bee died minutes later, but the nickname "Stonewall" stuck. Jackson's men held their ground. Later in the afternoon, the Rebels launched a counterattack that broke McDowell's force and triggered a panicked and confused retreat. The inexperienced Federals found their escape route clogged by the buggies of spectators who came from Washington to watch the action. The green Union troops may have had a difficult time of it, but the equally green Confederates did not pursue.
Casualties at Bull Run shocked the nation. The Union count came to 2,800, including 460 killed, and the Confederates had 1,900, with nearly 400 dead. Although future battles would make these numbers appear small, they were a wake-up call to a public, in both the North and the South, unprepared for such a bloody conflict.