Fast Facts about Mount St. Helens, the most active volcano in the Cascade Mountains in Washington.

Mount St. Helens is located in Washington, about 55 miles northeast of Portland, Oregon, and 95 miles south of Seattle.It is administered by the National Forest Service, not the National Park Service.Over the last 500 years, Mount St. Helens has had at least four major explosive eruptions and many minor eruptions.Mount St. Helens was named by Commander George Vancouver for British diplomat Alleyne Fitzherbert, whose title was Baron St. Helens.