Before revision: Terminology upright=1.1|At Harpers Ferry, West Virginia looking downstream, the Shenandoah River (bottom right) meets the Potomac River, which flows from bottom left to top right, making the Shenandoah a right tributary of the Potomac, not a left tributary.
After revision: ,Terminology upright=1.1|At Harpers Ferry, West Virginia looking downstream, the Shenandoah River (bottom right) meets the Potomac River, which flows from bottom left to top right, making the Shenandoah a right tributary of the Potomac, not a left tributary.