By late July 1863, both the Union Army of the Potomac and the Confederate Army of Northern Virginia had returned to Central Virginia. After the battles of Chancellorsville and Gettysburg, both armies were content to recruit and slowly gather strength. In September, Confederate General Robert E. Lee saw one-third of his army transferred to other sections of the Confederacy. In response, reinforcements from Union General George Meade's army were shipped to Tennessee.
Learning that his opponent was weakened, on October 9, 1863, Lee launched what would ultimately be his last offensive campaign of the Civil War. Trying to replicate the stunning success of the Second Manassas Campaign, Lee's army was concentrated near Warrenton on October 13 to prepare for the culminating battle of the campaign.