The Ohio River runs 981 miles from Pittsburgh, Pennsylvania, to Cairo, Illinois, where it joins the Mississippi.
The Ohio River watershed covers 205,000 square miles across 15 states: Pennsylvania, Ohio, Kentucky, West Virginia, Indiana, Illinois, Tennessee, New York, Virginia, Maryland, Georgia, Mississippi, Alabama, North Carolina and South Carolina.
The Ohio is commonly cited as the most polluted river in the United States.
The river supplies about five million people with drinking water.
