The three rivers in Pittsburgh are the Monongahela River, the Allegheny River and the Ohio River. The Monongahela River and Allegheny River meet in Pittsburgh to form the Ohio River, which travels 981 miles to its ending point in Cairo, Ill.
The Ohio River flows through or borders Illinois, Indiana, Kentucky, Ohio, Pennsylvania and West Virginia. The Monongahela River forms at the confluence of the West Fork River and the Tygart Valley River in Fairmont, Va., and flows a total length of 130 miles. The Allegheny River begins near the New York border in Potter County, Pa., and flows a total of 325 miles through New York and Pennsylvania.