Crater Lake National Park

Crater Lake National Park is a national park in the U.S. state of Oregon. It was created in 1902. It is the only national park in Oregon. The park includes the caldera of Crater Lake, the remains of the destroyed volcano Mount Mazama, and nearby hills and forests. 
The lake is deep. It is the deepest lake in the United States, the second deepest in North America and the ninth deepest in the world. The lake is so deep because of the caldera it is in.
Crater Lake has no streams flowing into or out of it. All water that enters the lake is eventually lost from evaporation or flowing away underground. The lake is re-filled only from snow and rain.