- a river flowing SE from the Allegheny Mountains in West Virginia, along the boundary between Maryland and Virginia to the Chesapeake Bay. 287 miles (460 km) long.
- a city in central Maryland, near Washington, D.C.
- a river in the E central US, rising in the Appalachian Mountains of West Virginia: flows northeast, then generally southeast to Chesapeake Bay. Length (from the confluence of headstreams): 462 km (287 miles)
