7. Libby Dam
Capacity: 5,809,000
Reservoir: Lake Koocanusa
State: Montana
The Libby dam stands in the way of Lake Koocanusa, which actually stretches a little bit into British Columbia, Canada. Therefore, some of its power goes to the American next-door neighbor. The dam was completed in 1972, and it is 422 feet tall, which makes an impressive view.
