Lee's retreat from Gettysburg was a lost opportunity for General Meade and his army. Having failed to destroy the Confederates north of the Potomac in July 1863, Meade maintained the momentum and attacked south in September.
President Lincoln watched in dismay as Lee retreated away from Gettysburg, back into Virginia. “Every day he has watched the progress of the Army with agonizing impatience, hope struggling with fear, ” his secretary John Hay recorded in his diary on July 14. “About noon came the despatch stating that our worst fears were true. The enemy had gotten away unhurt. The Prest was deeply grieved. 'We had them within our grasp, ' he said. 'We had only to stretch forth our hands & they were ours. And nothing I could say or do could make the Army move.'”
The Army of Northern Virginia finally felt safe, and Lee wrote to Jefferson Davis on July 16 from Bunker Hill, “The army is encamped around this place, where we shall rest today. The men are in good health and spirits, but want shoes and clothing badly. I have sent back to endeavor to procure a supply of both, and also horseshoes, for want of which nearly half our cavalry is unserviceable. As soon as these necessary articles are obtained we shall be prepared to resume operations.”
Resupply arrived, and Lee started further south, writing from Culpeper on July 24 that he planned to halt there and rest for a few days. In the meantime, General Meade had been spurred on to continue his pursuit of Lee by Lincoln's constant requests. “I learn that the enemy is massing a large army between Centreville and Manassas Junction, ” Lee wrote Davis. “A portion of General Meade's army crossed the Potomac as low down as the Chain Bridge [upriver from Washington], and I understand embraces the commands of Generals Dix and Foster. It would seem to have been the intention of the enemy to penetrate the Shenandoah Valley above Winchester, for in addition to these preparations I am informed that last evening he advanced three corps into Manassas Gap.”