The Ocmulgee River (/ɒkˈmʌlɡiː/) is a western tributary of the Altamaha River, approximately 255 mi (410 km) long, in the U.S. state of Georgia. It is the westernmost major tributary of the Altamaha. It was formerly known by its Hitchiti name of Ocheese Creek, from which the Creek (Muscogee) people derived their name.
The Ocmulgee River and its tributaries provide drainage for some 6,180 square miles in parts of 33 Georgia counties, a large section of the Piedmont and coastal plain of central Georgia.