Oreille.

This is coolbert.

Submarines? The land-locked USA state of Idaho? Idaho?

From jalopnik.com the article by Tyler Rogoway 6/14/14.

"The Navy's Most Vital And Secretive Submarine Base Is In... Idaho?!?"

"The US Navy's submarine bases are some of the most high-security installations in the world, but one of their most important and shadowy submarine outposts is not located along the ocean, but rather in a lake in landlocked Idaho."

"The Navy's Acoustic Research Detachment (ARD) at Bayview, Idaho, which is some 375 miles from the ocean, is where new submarine and surface ship shapes and subsystems are tested in a sub-scale environment that closely mimics the ocean. In other words, ARD Bayview is the Navy's lower-key subsurface Area 51, and massive Lake Pend Oreille is a water based, smaller, and more outsider friendly Nellis Range Complex."

"The lake's depth (it's deeper than Loch Ness at about 1150 feet/400 meters) , large size, clear water and quiet conditions provided by steep tree-lined shores and a flat muddy bottom, along with a constant chilly temperature under 100 feet, are all key factors that have made it such an attractive testing location for the US Navy since WWII. Also, the lake stays remarkably calm for its size, allowing for fantastic testing conditions."

Being away from the coastline [Atlantic and Pacific both] too negates any possibility of submarines of a foreign power hostile to the USA doing espionage while testing in progress.

See also the role of the Farragut naval training facility WW2 located at Lake Pend Oreille. Basic "boot" training for raw recruits yeoman naval service: "second-largest training center in the world". Everyone involved did themselves proud. The tradition continues. And so far from the ocean also!

coolbert.