Baku, June 3, AZERTAC The deepest lake in the United States and the seventh deepest lake in the world is at Crater Lake National Park in Southern Oregon at the Cascade Mountains.The lake lies inside a caldera, or volcanic basin, and was created when the 12,000 foot high Mount Mazama collapsed 7,700 years ago following a large eruption. Because the lake is filled almost entirely by snowfall, it is one of the clearest lakes in the world.Crater Lake National Park is comprised of 183,224 acres of mountains, peaks, evergreen forests, and lake. The ranging elevations throughout the park provide diverse habitats for an array of wildlife and make for an outstanding outdoor laboratory and classroom.