The Allegheny River is a 325-mile-long (523 km) headwater stream of the Ohio River that is located in western Pennsylvania and New York in the United States. It runs from its headwaters just below the middle of Pennsylvania's northern border, northwesterly into New York, then in a zigzag southwesterly across the border and through Western Pennsylvania to join the Monongahela River at the Forks of the Ohio at Point State Park in Downtown Pittsburgh, Pennsylvania.

The Ohio River is a 981-mile-long (1,579 km) river in the United States. It is located at the boundary of the Midwestern and Southern United States, flowing in a southwesterly direction from western Pennsylvania to its mouth on the Mississippi River at the southern tip of Illinois. It is the third largest river by discharge volume in the United States and the largest tributary by volume of the north-south flowing Mississippi River, which divides the eastern from western United States. It is also the 6th oldest river on the North American continent. The river flows through or along the border of six states, and its drainage basin includes parts of 14 states. Through its largest tributary, the Tennessee River, the basin includes several states of the southeastern U.S. It is the source of drinking water for five million people.