Mill Creek Wilderness - Geology

Geology

Mill Creek Wilderness features some unique geological features. Popular among visitors are the 200-foot (61 m) tall volcanic plugs in the northwest portion of the Wilderness, Twin Pillars. Thundereggs, the state rock of Oregon, have been found in the Wilderness at Desolation Canyon and just outside the boundary at Steins Pillar. Rockhounding is no longer permitted.

There are several gemstone mining claims located in Mill Creek Wilderness. The claims are all small surface operations and access is provided by primitive roads.