An early battle in the campaign that ended at the second battle of Bull Run. While General McClellan advanced towards Richmond, the scattered Union armies around the Shenandoah Valley had been reorganised and combined under the command of General John Pope. At the start of July the newly organised Army of Virginia came together between the Rapidan and Rappahannock Rivers, where it could threaten Robert E. Lee’s communications with the Shenandoah Valley, one of his main sources of supply.
Unfortunately for Pope, McClellan’s campaign outside Richmond had already come to grief. The Seven Days’ Battles at the end of June had forced him away from Richmond and into his camp on the James River. This gave Robert E. Lee a chance to dispatch Stonewall Jackson west to deal with the threat from Pope. On 13 July Jackson, with 12,000 men, was sent to Gordonsville, south of Pope’s position.
By now Pope had 50,000 men, but they were not concentrated at any one place. Jackson became convinced that he would be able to defeat part of Pope’s force if given the chance. Lee agreed, and sent him another 12,000 men, bringing his total force up to 24,000. He was still outnumbered two to one by Pope, but was strong enough to risk an attack on any isolated part of Pope’s command.
He got that chance on 9 August. General Banks, with 8,000 men, was posted eight miles south of Culpeper, at Cedar Mountain near the Rapidan River. However, Banks beat him to the punch. As Jackson’s men approached, he launched a surprise attack that came close to breaking Jackson’s old ‘Stonewall’ brigade. However, Banks had launched his attack under the misapprehension that reinforcements were near. When that turned out not to be the case, he was unable to stand against Jackson’s own attack. Banks was forced to retreat, until he did finally meet up with some reinforcements. Jackson was unable to follow up. He soon discovered that there were enough Federal troops close by to defeat him if he was caught, and so on 11 August he retreated back to Gordonsville.
Both sides suffered serious losses. Pope lost 320 dead, 1,466 wounded and 617 missing, for a total of 2,403. Jackson lost a similar number of dead (314) but fewer wounded and missing (1,062 and 42 respectively). Although Jackson had failed in his main objective, to defeat part of Pope’s army, the fighting at Cedar Mountain encouraged Robert E. Lee to join Jackson and concentrate against Pope, taking advantage of the period while McClellan’s Army of the Potomac was travelling back from the Peninsula.