Crater LAKE National Park is a national park located in southern Oregon, USA. It is the fifth oldest national park in the United States and is known for its deep blue LAKE, which was formed by the collapse of a volcano. The LAKE is the centerpiece of the park and is the deepest LAKE in the United States, with a depth of 1, 949 feet. The LAKE is fed by rain and snow and has no inlets or outlets. The LAKE's name comes from the caldera, or crater, that was formed when the volcano collapsed.