 This was easier done in the less rugged coastal plain of the Tidewater region and Piedmont terrain east of the Blue Ridge Mountains, which formed a formidable barrier to the west.Settlement of the Shenandoah Valley, between the Blue Ridge Mountains and the eastern edge of the Appalachian plateau, was done by pioneers who migrated south from Maryland and Pennsylvania via the head of the Potomac River and the valley of the Shenandoah River, rather than across the Blue Ridge.The Valley Turnpike ran along part of this corridor, chiefly following the route of an old Native American trail.