The Lake Pend Oreille lies in northern Idaho, surrounded by rugged mountains shaped by tectonic uplift and glacial erosion. Pronounced “Pond Or-RAY,” the lake was carved by massive Ice Age glaciers that deepened an ancient valley, creating one of the deepest natural lakes in the western United States. Its depth and steep surrounding slopes distinguish it from many other inland lakes. The Clark Fork River flows into the lake from Montana, bringing snowmelt from the Rocky Mountains. Water then exi