Trail #201 Eruption

Area Status: Unreachable
MSH from trail with interpretive sign

This popular paved accessible interpretive trail starts at the Johnston Ridge Observatory observation deck, ascending by way of paved switchbacks to the top of a ridge. This trail is a steep grade and some individuals may need assistance. 

Interpretive signs at this site record the May 18, 1980 eruption and volcanic history of the area. Enjoy impressive views of Mount St. Helens, the blast zone, Mount Adams, and the Mount Margaret Backcountry.

The trail continues eastward then descends to the junction with Boundary Trail #1. By staying on the paved path you will return to the main parking lot.

At a Glance

Current Conditions: 03/19/2024: Due to a significant landslide on State Route 504 around mile post 51 Johnston Ridge Observatory and the Eruption Trail are currently inaccessible. Learn More.
  • No fee or pass required, however site use at Johnston Ridge Observatory requires an America the Beautiful Pass or $8 per adult, children 15 and younger are free. An ANNUAL Northwest Forest Pass admits one.
Usage: Heavy
  • Off trail travel prohibited.
  • No pets or bicycles.
Closest Towns: Castle Rock, WA, Toutle, WA
Operated By: Forest Service
Information Center:

General Information

Johnston Ridge Observatory (State Route 504).


Day Hiking

Related Information

Recreation Areas

Recreation Activities


  Area/Length : 
0.5 miles

  Elevation : 
4200' - 4300'