Knobs, 2,490 feet (759 m) to its east. At Seneca Rocks, the North Fork is met by Seneca Creek. From Seneca Rocks, the North Fork continues to flow northeast along the western edge of North Fork Mountain 3,389 feet (1033 m) into Grant County. Flowing east through North Fork Gap, the North Fork joins the South Branch Potomac at the town of Cabins, west of Petersburg. South Fork South Branch Potomac River The South Fork South Branch Potomac River, sometimes called the South Fork River, forms just north of U.S. Route 250 in Highland County, Virginia near Monterey, and flows north-northeastward to the South Branch Potomac River at Moorefield in Hardy County, West Virginia. From 1896 to 1929, it was named the Moorefield River by the Board on Geographic Names to avoid confusion with the South Branch. See also List of crossings of the Potomac River § South Branch Potomac River References Rivers of Virginia Rivers of West Virginia Monongahela National Forest History of West Virginia Tributaries of the Chesapeake Bay