Step beneath the forest floor and discover one of the most unique adventures in the Mount St. Helens region. Ape Cave is a massive lava tube formed by ancient volcanic flows on the south side of Mount St. Helens, and at about 2.5 miles long, it is considered the third longest lava tube in North America. This unforgettable stop blends geology, adventure, and forest scenery into one of the area’s most memorable outdoor experiences.

The experience begins with a short paved path from the parking area to the cave entrance, where a stairway drops into a cool, dark underground world. From there, visitors can choose between two very different routes. The Lower Cave is the easier option, offering a relatively gentle out-and-back walk that is well suited for families and casual explorers. The Upper Cave is more challenging, with rocky footing, lava-formed obstacles, an 8-foot lava fall, and an exit ladder that brings you back to the surface for a forest hike to return to the main entrance.

Ape Cave is more than a hike. It is a chance to experience Mount St. Helens from the inside out. The cave stays around 42 degrees year-round, making it a refreshing summer adventure but one that requires preparation in every season. Visitors should bring warm layers and at least two reliable light sources per person, since there is no lighting inside the cave and cell phone flashlights are not considered adequate.

To help protect this fragile volcanic environment, visitors should avoid touching the cave walls or ceiling, and pets, smoking, camping, alcohol, and food or drinks other than water are not allowed inside. During the open season, timed entry reservations are required per vehicle, and parking also requires a Northwest Forest Pass, Interagency Pass, or day pass.

Whether you are looking for a family-friendly lava tube walk or a more adventurous underground scramble, Ape Cave offers a one-of-a-kind way to explore the volcanic story of Mount St. Helens. It is one of those places that feels equal parts trail, cave, and natural wonder.

Trail details: Ape Cave Trail #239, near Cougar, Washington. Main trailhead coordinates: 46.108645, -122.210387. The cave is reached via Forest Road 8303, roughly 9 miles east of Cougar.

Call to action: Add Ape Cave to your Mount St. Helens itinerary and experience one of the most unusual hikes in Washington, where volcanic history comes to life beneath your feet.

Current seasonal note: As of April 8, 2026, Ape Cave is in its winter closure period. The Forest Service page lists the site as seasonally closed from November 1 to May 17, while Recreation.gov currently says the 2026 summer season reopens on Friday, May 22 and requires timed tickets.

Lava Canyon is one of the most dramatic hikes on the south side of Mount St. Helens, where volcanic history, rushing water, and sheer rock walls come together in one unforgettable landscape. This striking canyon was shaped by lava flows and later scoured by the powerful forces unleashed during the 1980 eruption, leaving behind a rugged corridor of cliffs, waterfalls, and exposed canyon walls that feels both wild and otherworldly.

The experience begins at the Lava Canyon Interpretive Site, where the first section of trail offers an easy, paved, ADA-accessible walk into the canyon. This opening stretch is ideal for families, casual visitors, and anyone wanting a close-up look at the geology without committing to a strenuous hike. Along the way, interpretive signs help tell the story of how this landscape was formed, while viewpoints reveal the Muddy River cutting through basalt and ancient lava rock.

Beyond the paved section, Lava Canyon becomes more adventurous. The trail drops deeper into the canyon, with steeper grades, narrower tread, and dramatic views of waterfalls and churning water below. Under normal conditions, this area is known for its suspension bridge and thrilling canyon scenery, but the Forest Service currently notes that the suspension bridge is closed due to cable damage, so the old 1.4-mile upper loop is not possible right now. Visitors can still explore both sides of the river where open, but should expect to return the way they came rather than complete the full loop.

This is a trail that rewards respect and preparation. The Forest Service warns visitors to stay on the trail at all times, noting that going off trail is dangerous and that fatalities have occurred in the canyon area. Fast-moving water, steep drop-offs, and exposed sections make Lava Canyon a place to slow down, take in the views, and use caution every step of the way. Pets are allowed only on leash, and a Northwest Forest Pass, Digital Day Pass, or Interagency Pass is required for parking.

Whether you stop for the accessible interpretive walk or continue farther into the canyon for a more rugged experience, Lava Canyon offers one of the most visually powerful trail experiences in the Mount St. Helens region. It is a place where the mountain’s story is written into the stone, the water, and the shape of the land itself.

Trail details: Lava Canyon Trail #184, near Cougar, Washington. Trailhead coordinates: 46.1654, -122.0889.

Getting there: From I-5, take Exit 21 and head east on SR 503 toward Cougar. Continue through Cougar on Lewis River Road / Forest Road 90 past Swift Reservoir, then turn left onto Forest Road 83 and follow it to the Lava Canyon trailhead.

Call to action: Add Lava Canyon to your Mount St. Helens itinerary for a hike that combines volcanic geology, canyon drama, and some of the most memorable waterfall views on the mountain’s south side.

Current seasonal note: As of April 1, 2026, the Lava Canyon area is still under snow and Forest Road 83 is gated at Marble Mountain Sno-Park, so vehicle access to the trailhead remains closed for the season.

Trail of Two Forests

Location: Mount St. Helens National Volcanic Monument, Gifford Pinchot National Forest, Washington
Distance: 1.5 miles (Loop)
Difficulty: Easy
Elevation Gain: 100 feet
Family-Friendly: Yes
Open Season: Year-round (best from late spring to fall)
Trail Type: Loop

Overview:

This ¼ mile long boardwalk trail leads you over a 2,000-year-old lava flow from Mount St. Helens. Lava ran through the forest and around trees, which burst into flames. The lava solidified around the trunks and trunks rotted away, leaving tree wells, voids in which the impressions of the bark remain. Interpretive signs along the route tell the story of this ancient event. Climb down a ladder and go through a dark tree well. Enjoy today’s forest of fir, hemlock, and brilliant, green moss growing on the old lava. The boardwalk is accessible and kid friendly. Picnic tables and a pit-toilet are available. To protect fragile geologic features and plant life, please stay on the boardwalk.

Trail Highlights:

• Lava Tubes & Old Growth: The trail offers a glimpse into the past with its preserved lava tubes, remnants of the 1980 eruption, and thriving old-growth forests.
• Scenic Views: Enjoy views of the surrounding forest and volcanic landscape, with interpretive signs along the way providing insight into the area’s geology and ecology.
• Wildlife: Spot various wildlife, including birds, small mammals, and potentially elk or deer in the surrounding forests.

Details:

• Difficulty: Easy – The trail is gentle, well-maintained, and accessible for most hikers, including families and those with limited hiking experience.
• Elevation: Minimal elevation gain of only about 100 feet makes this a great option for a short, leisurely hike.
• Family-Friendly: Yes – This trail is ideal for families with children and those looking for a shorter, educational hike. The path is relatively flat and well-suited for beginners.
• Open Season: Open year-round, but the best hiking conditions are from late spring to fall, when the trail is dry and accessible. Winter weather can bring snow, so check conditions in advance.

Trail Type: Loop – Starting and ending at the same point, making it easy for those who prefer a short and self-contained hike.

The Trail of Two Forests is a fantastic introduction to the region’s volcanic landscape, offering a mix of natural beauty and educational value. Whether you're looking to explore the geology of Mount St. Helens or simply enjoy a short hike in the forest, this trail offers something for everyone.