Nōka ea Potomac e feta lik'hilomithara tse 383 ho tloha Fairfax Stone, Virginia Bophirimela ho Point Lookout, Maryland. E ama batho ba fetang limilione tse tšeletseng ba lulang ka har'a metsi a potoloho ea Potomac, sebaka sa lisekoere-k'hilomithara tse 14 670 moo metsi a kenang molomong oa nōka. 'Mapa ona o bontša sebaka sa nōka le sebaka sa eona sa leoatle se phallelang libakeng tse ngata tsa libaka tsa geolo ho akarelletsa le Plateau, Apparechian & Valleys, Blue Ridge, Piedmont le Coastal Plain.
Leqhoa le leholo le litlhōrō tse kholo tsa 12,878,8 ho etsa hore Nōka ea Potomake e kholo ka ho fetisisa United States. Libaka tse ka sehloohong tsa Nōka ea Potomac ke Ntla ea Leboea, Nōka ea Savage, Lekala la South, Cacapon, Shenandoah, Creek Antietam, Nōka ea Monocacy le Nōka ea Anacostia. Li-Potomac li kenella ka leboea la Chesapeake Bay .