Deschutes & Ochoco National Forests
Crooked River National Grassland

Geomorphic Provinces

The Central Oregon area includes parts of five geomorphic provinces:

• The southeastern portion of Central Oregon is part of the Basin and Range province of North America, which extends south well into Mexico. Walker Rim (south of Newberry) represents the most northwesterly extent of the Basin and Range province in Oregon.
• Much of eastern part of Central Oregon lies in the High Lava Plains province, which includes Newberry Volcano and the Brothers Fault Zone.
• To the northeast lies the Blue Mountains province of which the Ochoco Mountains are the western expression.
• To the north is the Deschutes-Columbia Plateau which includes the Deschutes Basin.
• The Cascade Range extends from northern California northward through Oregon and Washington into southern British Columbia. In Oregon the range can be divided into two distinct north-south trending belts:
  • The older, deeply eroded Western Cascades (to the west)
  • The young volcanoes of the High Cascades (to the east)