Interstate 5 (I-5) provides the best access routes to Mount St. Helens. These routes include the Lewis River Highway (State Highway 503) and the Spirit Lake Memorial Highway (State Highway 504). To access State Highway 503 take exit 21 off I-5 and to access State Highway 504 take exit 49 off I-5.
State Route 503 takes you to the town of Cougar, which is about 11 miles south-southwest of the mountain’s peak and is the community nearest to the volcano in the Lewis River valley.
State Route 504 takes you through the towns of Silver Lake and Toutle and past an array of visitor centers into the heart of the blast zone.
Amtrack train service offers the Coast Starlight route which runs from San Diego, California to Seattle, Washington. The closest depot to Mount St. Helens is Kelso, WA.
Amtrack also offers the Cascades route which runs between Vancouver, British Columbia and Eugene-Springfield, OR. The closest depot is Kelso, WA.