Elk Ridge, or Elk Mountain, is a mountain ridge of the Blue Ridge Mountains in Maryland and is the westernmost of four parallel ridges. It forms the western side of a narrow valley in which are situated the towns of Yarrowsburg and Brownsville. South Mountain is on the eastern side of this valley running roughly parallel to it. The ridge runs from Rohrersville, in the north, to the Potomac River across from Harpers Ferry, West Virginia, in the south. Across the Potomac the ridge continues as Blue Ridge Mountain in Virginia and West Virginia. To the west of Elk Mountain is the broader Cumberland Valley, in which lie the towns of Hagerstown and Chambersburg, and the Potomac River. The southern end of the ridge, which is part of Harpers Ferry National Historical Park, is known as Maryland Hei