After Robert E. Lee’s victory at Chancellorsville in May 1863, the Army of Northern Virginia moved west to the Shenandoah Valley, then north through Maryland into Pennsylvania, while George G. Meade, who replaced Joseph Hooker on June 28, led the Army of the Potomac in pursuit; the armies collided at Gettysburg on July 1, and after three days the defeated Confederates retreated across the Potomac into Virginia on July 14. As a gateway to the northern Shenandoah Valley, Chester Gap held great strategic importance during the Gettysburg Campaign. Between June 11 and June 19, Richard S. Ewell’s and A.P. Hill’s corps and James Longstreet’s wagon trains, amounting to far more than half of Lee’s army, passed through here on the march north, and after Gettysburg Longstreet and Hill retreated south by the same route, with Mountain Home at the northern base of the mountain serving as Longstreet’s headquarters. Meade planned to pin Lee’s army against the mountain near Front Royal and destroy it, but first had to block the gaps. A fierce fight in Manassas Gap on July 21 ended in a draw, and that afternoon William Gamble’s Union cavalry reached the eastern slopes of Chester Gap and found Montgomery D. Corse holding the pass. A 26-hour engagement followed until about 6 p.m. on July 22, when a detachment from Longstreet’s corps flanked Gamble’s forces and drove them back to Barbee’s Crossroads. Gamble delayed the Confederates and captured about 23 prisoners and more than 1,000 livestock, but Lee’s army escaped; Longstreet’s men moved quickly through on the way to Culpeper, Hill’s corps followed on July 23 with its progress slowed by wagon trains, and because the Federals did not attempt to block Thornton’s Gap, Ewell’s corps passed through there unchallenged on July 27.
