Watersheds
© Nicholas Tonelli West Branch, Susquehanna River
Nearly two-thirds of Pennsylvania drains into the Atlantic Ocean via the Potomac, Susquehanna and Delaware Basins. Much of the remainder of the western half of the state is drained through the Ohio Basin towards the Gulf of Mexico, while a small portion is drained to the north via the Erie and Genesee basins.
Learn more about Pennsylvania's major watersheds.
