... Mountains, which unite at its southwestern end. The Shenandoah Valley, which is a part of the Valley of Virginia, embraces the counties of Augusta, Rockingham, Shenandoah, Page, Warren, Clarke, Frederick , Jefferson and Berkeley. This valley is bounded on the north by the Potomac, on the south by the county of Rockbridge, on the east by the Blue Ridge and on the west by the Great North Mountain and ...