From the confluence of Allegheny and Monongahela Rivers to the Ohio/West Virginia border.
The Ohio River either flows through or borders Illinois, Indiana, Kentucky, Ohio, Pennsylvania, and West Virginia. As the main source of drinking water for more than three million people, almost 10% of the U.S. population lives within the Ohio River Basin.
In 1885, the first lock and dam was built on the Ohio River. By 1929, there were 46 locks and dams in the entire system. Currently, there are three sets of locks and dams within the Port of Pittsburgh Commission's district. The next phase for the locks on the Upper Ohio River are the replacements of the auxiliary lock chambers with larger chambers.