Hike in the Dark Side: Ape Caves

The Ape Caves Entrance

Exploring the Ape Caves

In the summer of 2022, Terri and I, along with our friends Geoff and Brenda, decided to take on the famous Ape Caves near Mount St. Helens. If you’ve ever wanted to feel like a subterranean explorer but without the risk of collapsing tunnels or needing a PhD in archaeology, this is the place for you.

What Are the Ape Caves?

The Ape Caves were formed about 2,000 years ago when Mount St. Helens had a lava flow. As the lava flowed downhill, the outer layer, exposed to the air, cooled and hardened while the hot, molten rock inside kept moving. Eventually, the hot inside lava drained out, leaving behind a hollow tube. What’s left today is a long, dark tunnel where lava once rushed through, shaping the walls into smooth rock and leaving behind eerie formations. Today, they offer the chance to walk through a geological marvel while simultaneously questioning your decision to spend part of a summer sunlit day in complete darkness.

The Ape Caves are located on the south side of Mount St. Helens, about an hour and a half drive from our home in Toledo, WA. While we have a great view of the mountain from our house, don’t be fooled into thinking there’s a quick way to get there—there’s no direct route. Instead, the drive takes you through winding forest roads, gradually climbing in elevation until you reach the Ape Cave Visitor Center. It’s a scenic drive, but don’t expect to shave off any time by going “as the crow flies” (or as the Sasquatch stomps).

Despite what the name suggests, the Ape Caves have nothing to do with actual apes—or at least, not the kind you’d find in a zoo. The caves were named after the St. Helens Apes, a local logging group known for their roughhousing and rowdy nature, which earned them the ape-like nickname. In the 1950s, a Boy Scout troop sponsored by the loggers explored and mapped the caves, naming them in honor of their sponsors. However, since the Pacific Northwest is a hotbed for Bigfoot lore, some like to imagine the caves as a secret Sasquatch hideout. So while the name has no official ties to Bigfoot, if you hear an eerie echo in the dark… well, let’s just say don’t find yourself as the tail end hiker in your band of explorers.

The Ape Cave lava tube is divided into two main sections:

• Lower Cave: About 0.75 miles (1.2 km) one way (1.5 miles round trip). This section is relatively easy, mostly flat, and great for beginners or families. It’s a manageable walk, though footing can be tricky with the uneven, rocky ground.

• Upper Cave: Around 1.5 miles (2.4 km) one way (3 miles round trip). This section is much more challenging, with large rock piles, an 8-foot rock wall to climb, and uneven terrain. To explore the upper cave, you’ll need decent endurance, balance, and flexibility to navigate the boulders and climb obstacles. If you have knee issues, mobility concerns, or just hate clambering over rocks in the dark, you might want to stick to the lower section.

Our Experience: Excitement, Wonder, and a Lot of the Same Rock

We entered the lower cave eager for mild adventure, equipped with headlamps and layered up like we were about to audition for a fall clothing catalog. At first, the caves were truly fascinating—dark, mysterious, and filled with the echoes of fellow adventurers fumbling through the darkness. But after about 20 minutes, a realization set in: it all looks the same. Rock, rock, another rock, a bend in the path, and—oh look—more rock.

That’s not to say it wasn’t interesting. The sheer scale of the caves and the cool, eerie atmosphere make for a unique experience. There are also a few unique features to look for as you hike along —such as the meatball rock. But unless you have a deep passion for volcanic formations, the excitement does plateau after a while.

The Meatball is a large lava boulder suspended over a passageway, which got lodged as lava flowed through the tube

Should You Go?

Absolutely! But here’s what you should know:

• Headlamps are a must. Flashlights work, but having both hands free is better, especially when maneuvering over uneven terrain.

• It’s chilly down there. Think crisp autumn day. The average temperature inside the Ape Caves is around 42°F (5.5°C) year-round. Layers will keep you comfortable. If it’s a hot day outside, you will want to remove a layer after being freed from the confines of the cave.

• Not for the claustrophobic. If the idea of being deep underground in an enclosed space gives you the heebie-jeebies, this might not be your ideal adventure.

• Manage expectations. It’s fun, but don’t expect non-stop thrills. Some sections feel repetitive.

Final Thoughts

The Ape Caves are worth experiencing at least once. They offer a glimpse into the fascinating geological history of the region and a fun, slightly eerie adventure. Just don’t expect Indiana Jones-level excitement—unless you count dodging the occasional low-hanging rock ceiling as an action-packed moment.

Would we go again? Probably not on our own. Are we glad we went? Absolutely.

If you’re in the Mount St. Helens area and want a unique adventure, grab a headlamp, wear some layers, and take a walk through the dark side!