In 1982 , U.S. President Ronald Reagan and the United States Congress made the Mount St. Helens National Volcanic Monument , a 110,000 acre ( 445 kmÂ ) area around the volcano that is also a part of the Gifford Pinchot National Forest . In 1982 , President Ronald Reagan and the U.S. Congress established the Mount St. Helens National Volcanic Monument , a 110000 a area around the mountain and within the Gifford Pinchot National Forest .