The park extends from Donner Lake up to Schallenberger Ridge to the south. Sierra Nevada's geologic history can be seen throughout the landscape:
- The granite that rose within the crust of the earth in enormous bubbles, then cooled and hardened, to be exposed by erosion.
- The older sedimentary rocks, transformed by temperature and pressure.
- The Sierra's steep eastern face, created when gigantic upheavals tilted a section of the earth's crust.
- The glaciers that dominated the area a few thousand years ago have left huge boulders and debris that remained when the ice melted.