Pittsburgh's Three Rivers by Ewingjr98
The Allegheny and Monongahela Rivers converge in Pittsburgh to form the Ohio River. The Allegheny River begins in northern Pennsylvania, enters New York and returns to Pennsylvania to drain almost 12,000 square miles of the Allegheny Plateau. The Monongahela River watershed covers over 7,000 miles of Maryland, West Virginia, and Pennsylvania and is one of the most industrialized areas of the US. The Ohio River begins in Pittsburgh and runs 981 miles to Cairo, Illinois.