Ohio River
The Ohio River begins at the confluence of the Allegheny and Monongahela rivers in Pittsburgh, Pennsylvania, flowing southwest, defining the boundaries of Ohio, West Virginia, Kentucky, Indiana, and Illinois before flowing into the Mississippi River in Cairo, Illinois. The watershed covers more than 200,000 square miles and provides drinking water for over five million people.
The Ohio River is rich in Indigenous history and culture. The word “Ohio” comes from the Seneca name for the river, Ohiyo, which means “it is beautiful.” The river provides critical habitat for 350 species of fish, including a variety of bass, catfish, and trout, and 120 mussel species. This critical watershed also protects endangered species such as the candy and diamond darter, several species of mussels, and crayfish.
Recreation is abundant on the Ohio River and contributes to local economies and quality of life through boating, fishing, paddling, and other outdoor activities that connect communities to the river.
What states does the Ohio River flow through?
The Ohio River flows through Pennsylvania, Ohio, West Virginia, Kentucky, Indiana, and Illinois.
How long is the Ohio River?
The Ohio River is 981 miles long.
Where does the Ohio River start and end?
The Ohio River starts in Pittsburgh, Pennsylvania, and ends in Cairo, Illinois, where it flows into the Mississippi.
Is the Ohio River a tributary of the Mississippi River?
Yes, the Ohio River is the largest tributary to the Mississippi River.
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The Ohio River was named as one of America’s Most Endangered Rivers®
The Ohio River was listed on America’s Most Endangered Rivers® of 2023 due to industrial pollution.
Ohio River Restoration Program Act
We named the Ohio River one of America’s Most Endangered Rivers® in 2023 — spotlighting the threats from industrial pollution — and it drove forward meaningful progress. Partnering with the Ohio River Basin Alliance, we brought together community leaders, conservation groups, and Congressional champions from both parties. This coalition achieved a breakthrough this year — the introduction of new legislation to restore and protect the Ohio River Basin, which 25 million people across 14 states depend on for drinking water, cultural connection, and vital wildlife habitat.
For years, we have worked with partners to improve water quality, fish passage, and resilient infrastructure — ensuring a healthy future for all. This legislation responds to the core needs of our communities and reflects our nation’s commitment to protect the Ohio River and the Ohio River Basin.