Susquehanna River, MD

The Susquehanna River is a river located in the northeastern United States. At approximately 444 mi (715 km) long, it is the longest river on the American east coast that drains into the Atlantic Ocean, and with its watershed it is the 16th largest river in the United States, and the longest river in the continental United States without commercial boat traffic. The Susquehanna forms from two main branches, with the North Branch, which rises in upstate New York often regarded as an extension of the main branch. The shorter West Branch, which rises in western Pennsylvania, is sometimes regarded as the principal tributary, joining the North Branch near Northumberland in central Pennsylvania. The river drains 27,500 square miles (71,225 km²), covering nearly half of the land area of Pennsylvania and portions of New York and Maryland. The drainage basin (watershed) includes portions of the Allegheny Plateau region of the Appalachian Mountains, cutting through water gaps in the lateral mountain ridges in a broad zigzag course to flow across the rural heartland of southeastern Pennsylvania and northeastern Maryland. The river empties into the northern end of the Chesapeake Bay, the ria of the Susquehanna, providing half of the freshwater inflow for the entire Chesapeake Bay.

Rising as the outlet of Otsego Lake in Cooperstown, New York, the north branch of the river runs west-southwest through dairy country, receiving the Unadilla River at Sidney and the Chenango in downtown Binghamton. At Athens Township (just south of Waverly, NY) in northern Pennsylvania, just across the New York state line, it receives the Chemung from the northwest and makes a right angle curve between Sayre and Towanda to cut through the Endless Mountains in the Allegheny Plateau. It receives the Lackawanna River southwest of Scranton and turns sharply to the southwest, flowing through the former anthracite industrial heartland in the mountain ridges of northeastern Pennsylvania, past Wilkes-Barre, Nanticoke, Berwick, Bloomsburg, and Danville. It receives the smaller West Branch from the northwest at Northumberland, just above Sunbury.

 Downstream from the confluence of its branches it flows south past Selinsgrove, where it is joined by its Penns Creek tributary, and cuts through a water gap at the western end of Mahantongo Mountain. It receives the Juniata River from the northwest at Duncannon, then passes through its last water gap, through Blue Mountain, just northwest of Harrisburg. It passes downtown Harrisburg (where it is nearly a mile wide), the largest city on the lower river, and flows southeast across South Central Pennsylvania, forming the border between York and Lancaster counties, as well as receiving Swatara Creek from the northeast. It crosses into northern Maryland approximately 30 miles (50 km) northeast of Baltimore, where it is joined by Octoraro Creek. Finally the river enters the northern end of the Chesapeake Bay at Havre de Grace, where Concord Point Light was built in 1827 to accommodate the increasing navigational traffic.