Mount St. Helens National Volcanic Monument

Mount St. Helens blew its top on May 18, 1980, and the monument around it shows a landscape still recovering from the blast. Families walk through lava tubes and old lava casts on the south side, and hikers can climb to the crater rim or walk the Loowit Trail all the way around the volcano.

Fast facts

• Established: 1982, two years after the eruption
• Size: about 110,000 acres (445 km²)
• Summit: 8,363 feet (2,549 m), about 1,300 feet (400 m) lower than before 1980
• Signature features: the crater and lava dome, Spirit Lake, the blast zone and Ape Cave
• Gateways: Castle Rock, Cougar and Randle
• Managed by: the Forest Service (Gifford Pinchot National Forest)

The landscape

The 1980 eruption removed the volcano’s north face and flattened forest across 230 square miles (600 km²). The north side is now a landscape of pumice plains, new lakes and regrowing forest, with the crater open to the north. The south side, spared by the blast, is older lava and forest, with lava tubes and tree casts from much older eruptions.

Best time to go

July to September is the main season, when snow has cleared from most trails and upper roads. The summer climbing route opens as snow melts, usually by late June. Winter brings snowshoeing and ski climbs on the south side, and the upper roads close.

Getting there and around

The north side is reached on SR 504 from Castle Rock (I-5 exit 49). The south side is reached from Woodland (I-5 exit 21) through Cougar on SR 503 and Forest Road 83. The east side is reached from Randle on Forest Roads 25 and 99 to Windy Ridge; these roads are closed by snow in winter. The three sides are not connected across the mountain by road.

Things to do

On the south side, walk the Trail of Two Forests past casts of trees buried by ancient lava, explore Ape Cave, a lava tube of about 2.5 miles (4 km) in total (the lower section is easier), and hike to June Lake or the upper, easier section of Lava Canyon. Viewpoints on the east and north sides look into the crater and across the blast zone.

The summit climb up Monitor Ridge is about 10 miles (16 km) round trip with about 4,500 feet (1,370 m) of climbing over boulders and loose ash, a long day but not technical in summer. The Loowit Trail circles the mountain in about 28 miles (45 km) of rough, exposed walking, usually over three or four days, and the Mount Margaret backcountry offers lake camps with views into the crater.

Staying safe

At the crater rim, snow cornices (overhanging lips of wind-packed snow) can collapse, so stay well back from the edge. The climb is on loose rock and ash with no shade or water. The Loowit Trail crosses washed-out gullies and has long waterless stretches. Weather changes quickly, with fog and wind on the upper mountain. In Ape Cave, bring two lights and warm layers; it stays near 42°F (6°C).

Know before you go

Anyone going above 4,800 feet (1,460 m) needs a climbing permit year-round; from April 1 to October 31 permits are limited and must be bought in advance on Recreation.gov. Camping in the Mount Margaret backcountry needs a permit. Ape Cave needs a timed reservation in the busy season, and most trailheads need a recreation pass. This page is a general overview, not a live conditions report, so confirm road access and permits with the Forest Service before you go.

Coordinates

46.2536, -122.2144

Magnetic declination

14.6° E (2026)

Set this declination on your compass, then align it to the map's north lines; it is the angle between true north and magnetic north, refreshed each year.

How declination works, and how to navigate with a map and compass

Best seasons

Summer, Early fall, Winter (snowshoe and ski climbs)

Difficulty

Easy to strenuous

Access / trailheads

North side via SR 504 from Castle Rock; south side via SR 503 and FR 83 through Cougar; east side via FR 25 and 99 from Randle (closed in winter). No road links the sides across the mountain.

Water

Scarce on the upper mountain and much of the Loowit Trail; carry plenty and treat stream water.

Cell / satellite coverage

Patchy; some signal on high ground facing I-5, little in valleys and on the south and east sides.

Nearest ranger / SAR / emergency

Emergencies: 911. Monument headquarters: 360-449-7800.

Permits & regulations

Climbing permit above 4,800 feet (1,460 m) year-round, limited and sold in advance April 1 to October 31. Backcountry camping permit for Mount Margaret. Timed reservations for Ape Cave in season; recreation pass at most trailheads.

Leave No Trace

Stay on trails in the recovering blast zone and pumice plains, where off-trail travel is restricted, pack out all waste, and camp only at designated sites.