• Left: Little Blue Run Lake in 1993, prior to dewatering
• Right: Little Blue Run Lake in 2019 after partial dewatering

Little Blue Run Lake or Little Blue Run is the largest coal ash impound in the United States. FirstEnergy owns the site, located in Western Pennsylvania and parts of the Northern Panhandle of West Virginia, and has disposed of billions of gallons of coal waste into the body of water. The lake contains 20 billion gallons of coal ash and smokestack scrubber waste. The northern coast of the lake is only a few hundred meters from the Ohio River, which is the drinking water source for more than three million people.