At 2.5 miles long, Ape Cave is the third longest lava tube in North America. Explore a chilly, pitch-black corridor deep beneath the forest floor of Mount St. Helens National Volcanic Monument. A short, paved trail leads to the entrance of the cave, where visitors must descend a series of staircases for self-exploration of the cavern. The 3/4 mile long Lower Cave is relatively easy and family-friendly; most visitors explore the Lower Cave in about an hour. For the more adventurous, the 1.5 mile Upper Cave involves scrambles over rock piles, scaling an 8 foot rock wall, and exiting a small opening in the ground surface before hiking 1.5 miles back to the entrance. The Upper Cave can take 2 hours or more to explore. Visitors must come prepared to explore the cave independently—there are no lights in the cave, so visitors must bring their own headlamps or flashlights. Cell phone lights are not adequate for the cave. More information on the cave can be found here .

To provide for public safety and to protect the delicate cave ecosystem and natural resources, tickets for Ape Cave are required for each vehicle parking on-site. Thank you for your cooperation!