Mount St. Helens National Volcanic Monument is a U.S. National Monument that includes the area around Mount St. Helens in Washington . It was established on August 27 , 1982 by U.S. President Ronald Reagan following the 1980 eruption . The 110,000 acre ( 445 km2 ) National Volcanic Monument was set aside for research , recreation , and education . Inside the Monument , the environment is left to respond naturally to the disturbance
1980 eruption
1980 eruption of Mount St. Helens
Mount St. Helens National Volcanic Monument