In northern Idaho!!!
The NSWCCD Acoustic Research Detachment (ARD) is located on Lake Pend Oreille, which is Idaho's largest, deepest (1,150 feet), and quietest body of water providing an ideal environment for acoustic testing without the attendant problems and costs of open ocean operations (U.S. Navy)
And it’s been there since World War II.
This surfaced because a 48-by-80 foot barge capsized. Some guesses are it was caused by an ice buildup.
More @ The Navy is investigating why a barge suddenly capsized at an Idaho stealth submarine facility
