The Panorama wayside is at the top of the pass. Here I found a Civil War Trails sign entitled Thornton Gap, Tactical Mountain Pass. It begins with this:
During the Civil War, this gap in the Blue Ridge was of significant tactical importance for the movement of troops, artillery and supply wagons. The Thornton's Gap Turnpike, a macadamized (hard-surfaced) turnpike passed through the gap and linked Luray in the Shenandoah Valley and Culpeper Court House in the central Piedmont. The Sperryville and Rappahannock Turnpike ran from Warrenton to a junction with the Thornton's Gap Turnpike at Sperryville.