Conococheague Creek, a tributary of the Potomac River, is a free-flowing stream that originates in Pennsylvania and empties into the Potomac River near Williamsport, Maryland. It is 80 miles (129 km) in length, with 57 miles (92 km) in Pennsylvania and 23 miles (37 km) in Maryland.
Conococheague Creek continues south into Maryland and enters the Potomac near Williamsport, where the Great Philadelphia Wagon Road crossed the river at William's Ferry, continuing on to Winchester, Virginia. The crossing is where Braddock's forces crossed the Potomac after leaving Frederick on their way to Winchester. The Tuscarora Trail crosses the Conococheague.