Ape Cave Lava Tube

The basics

The Gifford Pinchot National Forest area of Washington State has seen lots of volcanic activity over the past several millennia. To the north is the infamous Mount St. Helen's, which blew its top in an explosive eruption in May 1980. The National Forest contains the Ape Cave Lava Tube, created 2,000 years earlier in a fast-flowing basaltic lava flow—uncommon for this region—making the two large tubes.

A local logger discovered the cave in 1950, but it wasn't explored until a local Boy Scout troop went inside. It was named after the troop's sponsor, the St. Helens Apes, a possible reference to the legend of Bigfoot, or the term "brush apes," used for foresters at the time.

Things to know before you go

• An all-around light source, such as a lantern, provides the necessary light to maneuver safely in the cave and can be rented from a kiosk.

• The trail to the Ape Cave is accessible and kid-friendly, but those with mobility issues may have difficulty entering the cave.

• The cave maintains a constant 42°F (5°C) temperature inside, so be prepared with warm clothes, even in warm weather.

• Two-hour reservation slots ($2) from recreation.gov are required to visit Ape Cave during the open season, from May through October—check for specific dates online.

• This attraction is often paired with the nearby Trail of Two Forests Interpretive site and the superb view of Mount St. Helens, accessed on a trail in the parking lot.

• Parking is $5 daily or free with a valid Northwest Forest Annual Pass.

How to get there

Travel north and east on State Route 503 (also Lewis River Road) in Cougar, Washington for 2.8 miles (4.5 kilometers). This road will change to Forest Road 90. Continue on Forest Road 90 for 4 miles (6.4 kilometers) to Forest Road 83 and turn left. Drive another 3 miles (4.8 miles) on Forest Road 83 and turn left onto Forest Road 8303. Drive 1.5 miles (2.4 kilometers) past Trail of Two Forests, and the Apes Cave Headquarters will be on the left.

When to get there

The Ape Caves are open from May through October when roads are open and clear of seasonal snow. Summer is the busiest time at the site, so consider visiting during the week or outside the peak months of July and August for a quieter visit.

Take care in the fragile environment

The ecosystem of the Ape Cave is a fragile one. Inside are two creatures worth protecting—bats and wall slime. By not touching the cave walls and ceiling, visitors can keep the wall slime healthy, which is food for small creatures in the cave. The bats are susceptible to White Nose Syndrome, a fungal disease humans can pass on. Follow the guidelines posted regarding cleaning shoes and other precautions to ensure you do not transport harmful spores into the cave.