|Pennsylvania Civil War
The Gettysburg Campaign
Following his victory at Chancellorsville, Va., in May 1863, Robert E. Lee again decided to take his Confederate army, and the war, to the north.
Union cavalry discovered the movement and nearly defeated J.E.B Stuart at Brandy Station near Culpeper June 9. But Lee stuck to his plan, marching the bulk of his army north through the Shenandoah Valley where Confederate troops cleared out a Federal garrison June 14. Stuart screened this movement, fighting battles east of the mountains, at Upperville, Middleburg and Aldie June 17–21.
Confederate soldiers poured over the Potomac River near Williamsport June 15–25, moving on Hagerstown, then north into Pennsylvania. Union infantry under Gen. Joseph Hooker, still in command of the Federal forces, shadowed Lee's movement east of the mountains. Union infantry, filling the roads in central Maryland, marched north. Some Federal forces followed the route taken days earlier by Stuart's cavalry as he ranged far away from Lee's army in a fateful foray. Stuart, then the Union 5th Corps, camped at Union Mills, north of Westminister. Others marched through Frederick. Hooker was relieved of command there, replaced on June 28 by Gen. George Meade. That evening Lee was in Chambersburg. Learning Union forces had crossed the Potomac and were in pursuit, the Confederate commander ordered his army to concentrate.
Three days later elements of the armies stumbled into each other at Gettysburg.
Following the momentous three-day battle,
the Confederates retreated through Pennsylvania and Maryland, then across the Potomac at Falling Waters. Federal pursuit was halfhearted.
Union losses at Gettysburg totaled more than 23,000 troops. Lee had lost at least 28,000 soldiers, the strategic initiative and possibly the war.