Monongahela River

Length: 128 miles (206 kilometers)

The Monongahela (mah-nahn-gah-HEE-lah) River, north West Virginia, is formed at Fairmont by the joining of the West Fork and Tygart rivers and flows northeast past Morgantown and Star City and enters Pennsylvania. It receives Cheat River from the southeast and turns north, flows past Friendship Hill National Historic Site, past Fredericktown, California, Monessen, Monongahela, and Clairton; receives the Youghiogheny River from southeast at McKeesport, turns northwest at Duquesne, joins the Allegheny River in downtown Pittsburg to form Ohio River. The channelized river is navigable for most of its length. The Monongahela River was the first river in the United States to be improved for navigation.