By 4 P.M., the Confederates had the initiative, or momentum, and by 5 P.M., the Federals had begun a slow, dignified retreat. No one knows precisely how it happened, but some of the retreating men, finding supply wagons in their way, tipped them over, and it was now that a full-scale rout commenced.

A British journalist, reporting for the London Times, came to the battlefield late, and was appalled by what he saw: regiments disbanded, men on the run, and a general feeling of complete defeat. Some men threw their muskets or rifles away and simply ran. That night and the next morning found most of McDowell’s beaten force on or near the western side of the Potomac River, where they were safe, thanks to federal gunboats. Losses on the two sides were about equal, for a total of 6,000 men killed, wounded, and missing. This was much bloodier than had been expected.