The Allegheny River is a principal tributary of the Ohio River; it is located in the Eastern United States. The Allegheny River joins with the Monongahela River to form the Ohio River at the "Point" of Point State Park in Downtown Pittsburgh, Pennsylvania. The Allegheny River is, by volume, the main headstream of the Ohio River.GeographyThe river is approximately long, running through the U.S. states of New York and Pennsylvania. It drains a rural dissected plateau of 11580sqmi in the northern Allegheny Plateau, providing the northeastern most drainage in the watershed of the Mississippi River. Its tributaries reach to within of Lake Erie in southwestern New York.The Allegheny Valley has been one of the most productive areas of fossil fuel extraction in United States history, with its extensive deposits of coal, petroleum, and natural gas.
