On what mountain will you find Crater Lake?

You will find Crater Lake on Mount Mazama, a collapsed volcano in southern Oregon. Mount Mazama once stood roughly 12,000 feet high in the Cascade Range, but a massive eruption about 7,700 years ago emptied much of the volcano's interior and caused its summit to collapse.

The collapse created a caldera, or broad volcanic basin, that gradually filled with rain and snowmelt. Crater Lake now occupies that basin and reaches 1,943 feet deep, making it the deepest lake in the United States. Wizard Island, the small cone rising from the lake, formed from later volcanic activity inside the caldera.

A common mix-up is to name Mount Scott, the highest remaining mountain in Crater Lake National Park. Mount Scott rises to 8,929 feet, but it is not the volcano that formed the lake. Mount Mazama is the correct geological source, even though much of the original mountain no longer exists.