Susquehanna River near White Deer, Pennsylvania (USA)
The Susquehanna River (originally "Sasquesahanough" on the 1612 map by explorer John Smith who traveled up the river from the Chesapeake Bay) is located primarily in Pennsylvania. At approximately 444 mi (715 km) long, it is the longest river on the American east coast and the 16th longest in the United States. This is a view of the west branch of the river near the village of White Deer (map). In the distance upstream is the route 44 bridge to the village of Dewart. That's about one hour north of Harrisburg, the state capitol (which is also located along the Susquehanna).
Geologically speaking, the Susquehanna is one of the oldest rivers in the world, cutting through mountain ridges which which were formed in uplift events of the early Cenozoic era. There is evidence that the flow of the ancient Susquehanna was established early enough that it predated the Appalachian orogeny over 300 million years ago, meaning that the river was in existence well before Pangea broke up and formed the Atlantic Ocean.
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