No major river link Pennsylvania to Washington, D.C., in a direct manner. The Potomac River flows through the city and several of its tributaries have their origins in south central Pennsylvania. The waterways in that region of the state are part of the Potomac Watershed, which in turn are a small part of the vast Chesapeake Bay Watershed. The Pennsylvania section accounts for about eleven percent of the total Potomac Watershed management area.

Seven Pennsylvania counties have tributaries of the Potomac Watershed within their boundaries. These are, from east to west: Adams, the southeastern tip of Cumberland, Franklin, Fulton, Bedford, and the southwestern corner of Somerset.

The creeks like Toms, Marsh, and Rock Creeks in Adams County empty into the Monocacy River which in turn empties into the Potomac River. Of these creeks only portions are navigable by kayak or canoe. For instance, Marsh Creek, a Class II-III whitewater creek, has only 3.8 miles of its length which can be traveled.

The creeks, runs, and brooks in the other counties of the Potomac Watershed area flow either into each other and then join the Potomac or flow directly into the river as it winds its way toward Washington, D.C. Some, like Antietam, Conococheague, Big Cove, and Tonoloway Creeks, have whitewater sections which can be navigated.

The whitewater paddler who wishes to navigate a Pennsylvania creek to its juncture with the Potomac and follow the river to Washington, D.C., should consult with local shops which rent kayaks or canoes or offer tours of Pennsylvania waterways. They will know which of the local creeks have sufficient water levels for safe navigation. Whitewater paddling clubs in Maryland or Pennsylvania will have this information also. Some portaging may be required in places.