The Elk River is a tidal tributary of the Chesapeake Bay on the Eastern Shore of Maryland and on the northern edge of the Delmarva Peninsula. It is about 15 miles (24 km) long. As the most northeastern extension of the Chesapeake Bay estuary, it serves as one entrance to the Chesapeake and Delaware Canal.
The Elk River begins at the confluence of Big Elk Creek and Little Elk Creek in Elkton, and ends at the Chesapeake Bay at a 1.4 miles (2.3 km) wide mouth between Turkey
Point on Elk Neck and West View Shores/Sunset Point. Little Elk Creek rises near Oxford, Pennsylvania, and the East Branch and West Branch of Big Elk Creek rise to the south of Cochranville, Pennsylvania.