Navy's Area 51 in . . . Idaho?

https://www.repi.mil/Portals/44/Documents/Buffer_Fact_Sheets/Navy/ARD_Bayview.pdf

ACOUSTIC RESEARCH DETACHMENT : IDAH PDF

https://www.navsea.navy.mil/Home/Warfare-Centers/NSWC-Carderock/Who-We-Are/Bayview-Idaho/

Acoustic Research Detachment - Bayview, Idaho

https://www.onlyinyourstate.com/idaho/id-underwater-navy-research/

Idaho Has An Underwater Area 51 And It’s Fascinating

The Gem State is just full of surprises! Few would expect the United States’ top submarine outpost to be tucked away in the panhandle of landlocked Idaho, but this advanced facility has quite a unique history. And it’s at the bottom of Lake Pend Orielle in Idaho, no less!

In fact, before these underwater military vessels can be added to the naval fleet, each piece of state-of-the-art technology onboard must be tested under open water conditions without venturing into the dangerous ocean territory. It’s a small-scale Area 51 that few people know about but is an incredibly fascinating part of Idaho that serves a national purpose. It's called the U.S. Navy Acoustic Research Detachment (ARD). Lake Pend Oreille is Idaho’s largest, deepest, and quietest body of water, making it perfect for top-secret underwater missions.