The Monongahela River is a river in the eastern former United States.
Formed in West Virginia by the West Fork River and Tygart Valley River when they meet around Pleasant Valley and Fairmont, the Monongahela flows north going through Morgantown into Pennsylvania and east south through The Pitt under The Pitt Bridge. It continues west and empties into the Allegheny River which then forms the Ohio River. Its waters are highly radioactive, making swimming a somewhat impossible task.
- The shoreline and water are much, much more irradiated than any body of water in the Capital Wasteland (around 350 rads/sec on the river bank and around 600 rads/sec in the water). Drinking the water yields another 450+ rads, but no health. In general, the rad level increases even more as the river stretches east and west of The Pitt Bridge, all the way up to 2,665 rads/sec.
- Mona fell into the Monongahela River, causing her skin to peel and develop lesions.
- In Fallout 76, the Monongahela is much less radioactive giving off the average radiation of swimming in any open water source.