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.
Northern California Northern California, often abbreviated NorCal, is the northern portion of the U.S. state of California. Spanning the state's northernmost 48 counties, in contrast to the 10 counties of Southern California, its main population centers include the San Francisco Bay Area (anchored by the cities of San Francisco, San Jose, and Oakland), the Greater Sacramento area (anchored by the state capital Sacramento), and the Metropolitan Fresno area (anchored by the city of Fresno). Northern California also contains redwood forests, along with the Sierra Nevada, including Yosemite Valley and part of Lake Tahoe, Mount Shasta (the second-highest peak in the Cascade Range after Mount Rainier in Washington), and most of the Central Valley, one of the world's most productive agricultural regions.