What three states are covered by the volcano range including the North Cascades?
Cascades Volcano Observatory The David A. Johnston Cascades Volcano Observatory is the volcano observatory that monitors volcanoes in the northern Cascade Range. Its territory covers Oregon, Washington, and Idaho. The Cascade range's southernmost reaches extend into Northern California, and Cascade volcanoes south of the Oregon-California border—such as Mt. Shasta—previously fell into CVO's jurisdiction. However, as of February 2012, these volcanoes fall under the jurisdiction of the newly formed California Volcano Observatory (CalVO), based in Menlo Park, CA which monitors and researches volcanic activity throughout California and Nevada.
Olympic National Forest Olympic National Forest is a U.S. National Forest located in Washington, USA. With an area of 628115 acre , it nearly surrounds Olympic National Park and the Olympic Mountain range. Olympic National Forest contains parts of Clallam, Grays Harbor, Jefferson, and Mason counties. The landscape of the national forest varies, from the temperate Olympic rain forest to the salt water fjord of Hood Canal to the peaks of Mt. Washington.