Explore the Ape Cave of Mt. St. Helens

Mount St. Helens’ Ape Cave is a remarkable natural landmark currently the longest continuous lava tube in the continental United States. Visitors are encouraged to walk through and explore this unique passage while taking in the sights in Gifford Pinchot National Forest.

The tube itself is roughly two miles long and divided into two separate sections, the Upper and Lower Caves. The Upper Caves, making up the bulk of the journey, are 1.5 miles in length and contains the most varied formations in the tube. Along this portion you’ll have to climb over rock piles and try not to slip while maneuvering down an 8-foot lava fall.

In the second portion of the tube, things get a little tighter. The ceilings here are lower but the path itself is smoother and only slightly slanted. The Lower Cave is not quite as adventurous at the Upper, but you’ll see some pretty cool sights. Don’t miss out on “Meatball,” a portion of lava rock that fell from the ceiling while lava was still cool in the tube.

There are a few rules to keep in mind. The walls are made of cave “slime,” which serves as food for the local ecosystem and cannot be touched. You’ll also want to bundle up as the temperatures in the cave remain constant at 42 degrees and there are plenty of spots where water drips from the ceiling. With only one skylight that opens to the outside world in the middle of the cave you’ll also need to bring light sources with you.

Once you’re out you’ll have a short trek back to the beginning and a fun story to share with your friends.