Susquehanna River

The Susquehanna River (; Lenape: ) is a major river located in the Mid-Atlantic region of the United States, overlapping between the lower Northeast. At long, it is the longest river on the East Coast of the United States. By watershed area, it is the 16th-largest river in the United States, and also the longest river in the early 21st-century continental United States without commercial boat traffic. The Susquehanna River forms from two main branches: the North Branch, which rises in Cooperstown, New York, and is regarded by federal mapmakers as the main branch or headwaters, and the West Branch, which rises in western Pennsylvania and joins the main branch near Northumberland in central Pennsylvania. The river drains , including nearly half of the land area of Pennsylvania. The drainage basin includes portions of the Allegheny Plateau region of the Appalachian Mountains, cutting through a succession of water gaps in a broad zigzag course to flow across the rural heartland of southeastern Pennsylvania and northeastern Maryland in the lateral near-parallel array of mountain ridges. The river empties into the northern end of the Chesapeake Bay at Perryville and Havre de Grace, Maryland, providing half of the Bay's freshwater inflow. The bay lies in the flooded valley, or ria, of the Susquehanna. Geology The Susquehanna River is one of the oldest existing rivers in the world, being dated as 320–340 Myr, older than the mountain ridges through which it flows. These ridges resulted from the Alleghenian orogeny uplift events, when Africa (as part of Gondwana) slammed into the Northern part of Euramerica. The Susquehanna basin reaches its ultimate outflow in the Chesapeake Bay. It was well established in the flat tidelands of eastern North America during the Mesozoic era about 252 to 66 million years ago. This is the same period when the Hudson, Delaware and Potomac rivers were established.