St. Helens Ape Cave Hike

Ape Cave Lava Tube Hike - Trail 239

The Ape Caves were formed about 2,000 years ago when basaltic lava came pouring out of Mount St. Helens. As the flow proceeded, the surface cooled, forming a crust. The lava underneath the crust continued moving through the tube for months. When the eruption finally ceased, it left a 13,042-foot lava tube.

The full experience at Ape Cave includes the easy exploration of a spacious lava tube, followed by more difficult travel through a smaller, longer, and more rugged lava tube to an exit. Then, enjoy an easy return hike winding through shady forest and crusty lava formations.

The temperature is a constant 42 degrees F. The ceilings are drippy, and there may be puddles. Bring 2 or 3 light sources and spare batteries. No cave can ever be considered completely safe. A short distance from the parking lot, enter the large cave entrance and descend two staircases to the floor of the cave and the signed junction between Upper and Lower.

Ape Cave Lava Tube Information

·         Restrictions: No food, pets, smoking

·         Lave Tube Length: 13,042 feet long (about 2.4 miles)

·         Ape Cave is the third longest lava tube in North America

·         Location: Gifford Pinchot National Forest Washington

·         Mount St. Helens National Volcanic Monument

·         Trail Head: Mount St. Helen's - Ape Caves Trail-head

·         Lower Cave 0.8-mile hike

·         Upper Cave 1.5-mile hike 

·         Elevation Change: 400' Elevation gain

·         Season: Year Round

·         Parking Pass/Entry Fee - Northwest Forest Pass

·         Complete darkness

·         Dripping Water and blowing breezes

·         Click here to see more information on Ape Cave National Volcanic Monument

Lower Ape Cave Hike: It's a broad lava tube that descends gently to its end. The floor is flat (though a bit uneven at first), then sandy later on, from a mud flow that filled the lower portion centuries ago. The end of the cave now is where the sand has filled in to within a couple feet of the ceiling. The Lower Cave is an easy walk, for a 1.5-mile round trip, that houses a popular geologic anomaly known as the Meatball.

Upper Ape Cave Hike: It's a 1.5 rugged miles one way, requiring significantly more time and caution to hike. This unique hike up an ancient lava tube takes you over many piles of sharp cutting lave boulders. About 2/3 of the way up this hike you will come to an 8-foot wall. Be warned, that the climb up this wall is not easy. This route requires good scrambling ability.

While follow the trail, eventually you will come to a place where there is a hole in the ceiling of this cave. From that point it is only a short walk to the iron ladder that will take you out of the lava tube and place you firmly on the top, where you just follow the clearly marked path back to the point where you began this adventure.

Driving Directions: From I-5 exit 21, travel north and east on State Route 503 (Lewis River Road). At 23 miles from the freeway, continue straight on Spur 503. At 31 miles, Spur 503 becomes Forest Road 90. Cross a bridge over a canal, then 2.6 miles later, turn left on FR 83. Travel 1.7 miles then turn left on FR 8303. Travel the final mile to the parking lot and Ape Headquarters Center. The parking lot has room for 50-60 vehicles, including bus and RV spots. There are vault toilets and garbage cans, but no drinking water. When it’s open, Ape Headquarters Center offers rental lanterns.

Address : Ape Caves, Cougar, WA 98616, USA