Kogin Potomac ya wuce kilomita 383 daga Fairfax Stone, West Virginia zuwa Point Lookout, Maryland. Yana shafar mutane fiye da miliyan 6 da suke zaune a cikin ruwa na Potomac, inda ke da kilomita 14,670-kilomita inda ruwa ya kwarara zuwa bakin kogin. Wannan taswirar ya nuna wurin da kogi da kuma yankin da ke kan iyakokin da ke kewaye da yankunan geological da suka hada da Plateau, Ridge & Valleys, Blue Ridge, Piedmont, da Coastal Plalain.
Babban kuma ya hada da manyan masu adawa da kundin tsarin mulki 12,878.8 mil da ke sa Potomac River ya zama mafi girma a 21 a Amurka. Babban masu adawa da Kogin Potomac sune Branch Branch, Savage River, South Branch, Cacapon, Shenandoah, Antietam Creek, Kogin Monocacy, da Anacostia River. Potomac ya shiga cikin Chesapeake Bay a gefen ƙasa.