Lake Pend Oreille, lake in Kaniksu National Forest, northwestern Idaho, U.S. The largest lake in Idaho, it is about 40 miles (65 km) long and 4 miles (6.5 km) wide and covers an area of some 125 square miles (325 square km).

Where do they test submarines in Idaho?

During the middle of the night the small scale, unmanned sub glides through the cold, dark waters of Idaho's deepest lake, Lake Pend Oreille. Idaho? Yes, for over 65 years the south end of the lake has been the premier testing ground for acoustic development of the Navy's submarines.

What's the deepest lake in Idaho?

Lake Pend Oreille is Idaho's biggest, at 43 miles long with 111 miles of shoreline. It's also the deepest (at 1,158 feet deep, there are only four deeper lakes in the nation).