That lake is 5th deepest in U.S.
https://en.wikipedia.org/wiki/Lake_Pend_Oreille
Lake Pend Oreille (pronounced: pond-o-ray) is a lake in the northern Idaho Panhandle, with a surface area of 148 square miles (380 km2). It is 43 miles (69 km) long, and 1,150 feet (350 m) deep in some regions, making it the fifth deepest in the United States.
Yeah, that’s true, most of the shoreline is unpopulated (must be hard to believe for people in different parts of the country).
Continuing the travelogue...
Schweitzer Mountain Ski Resort just outside of Sandpoint, ID is excellent also. Sandpoint is an excellent town to stay in and is right on the lake shore (lake often partially frozen during ski season — not sure if it ever freezes across the entire surface).