Castle Rock is part of the Pacific Ring of Fire that includes over 160 active volcanoes and is in the Klastline Group of the Northern Cordilleran Volcanic Province and last erupted in the Pleistocene.
Castle Rock is part of the Pacific Ring of Fire, a region with numerous active volcanoes. It belongs to the Klastline Group in the Northern Cordilleran Volcanic Province and experienced its most recent volcanic activity during the Pleistocene period.