Mount St. Helens National Volcanic Monument is accessed by three different routes. The one with the major information centers is Wash. 504, the Spirit Lake Highway, which heads east from I-5 at Castle Rock. The southern section of the monument is reached via Wash. 503 from I-5 at Woodland. The east side of the monument is reached via U.S. 12 from I-5 at exit 68.
For more information on the national monument, contact Mount St. Helens National Volcanic Monument, 42218 NE Yale Bridge Rd., Amboy, WA 98601 (tel. 360/449-7800; www.fs.fed.us/gpnf/mshnvm).
Admission to the monument is $8 for adults and free for children 15 and under. If you just want to park at one of the monument's trail heads and go for a hike, all you need is a valid Northwest Forest Pass, which costs $5 per day. If it's winter, you'll need a Sno-Park Permit ($8-$9 per day).
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.