Mtsinje wa Potomac umayenda makilomita oposa 383 kuchokera ku Fairfax Stone, West Virginia kupita ku Point Lookout, Maryland. Zimakhudza anthu oposa 6 miliyoni omwe amakhala mumtsinje wa Potomac, malo okwana makilomita 14,670 pomwe madzi akuthamangira kumtsinje. Mapu awa amasonyeza malo a mtsinjewu ndi malo ake omwe mumadutsa madzi omwe amapita kudera linalake monga Appalachian Plateau, Ridge & Valleys, Blue Ridge, Piedmont, ndi Coastal Plain.
Chitsamba chachikulu ndi mabwinja onse akuluakulu 12,878.8 miles kupanga mtsinje wa Potomac waukulu kwambiri 21 ku United States. Mtsinje waukulu wa Potomac ndi North Branch, Mtsinje wa Savage, South Branch, Cacapon, Shenandoah, Mtsinje wa Antietam, Mtsinje wa Monocacy, ndi Mtsinje wa Anacostia. Kumalo otchedwa Potomac kumalo otsetsereka a Chesapeake .