Crater Lake National Park in southern Oregon preserves Crater Lake, the caldera of collapsed Mount Mazama, and a surrounding volcanic and forested landscape. Formed about 7,700 years ago by a catastrophic eruption that spread ash across much of the West, the caldera later filled with rain and snow, creating the deepest lake in the United States. Established in 1902 as Oregon’s only national park and the nation’s fifth oldest, it also holds notable volcanic features, scenic rim roads, and trails. The park’s history includes Klamath traditions about the mountain’s destruction, early prospectors, and William Gladstone Steel’s long campaign to secure federal protection.