Question: The Piedmont Mountains are outlying mountains, sometimes called “low mountains”, that typically occur in the western Piedmont near the Blue Ridge, The Piedmont is part of the greater Appalachian Mountain Range and is also referred to as the Appalachian Plateau, it's a series of rugged, high plains located on the western side of the which location?
Sentence (from "Catoctin Mountain"): The ridge forms the eastern rampart of the Loudoun and Middletown valleys.
Relevant evidence: No