Imagine being the logger who, in 1947, stumbled upon a deep, dark cavern in the wilderness just south of Mount St. Helens. Or put yourself in the boots of the first scout troop member lowered to the cave floor a few years later — the inky blackness swallowing the blaze of flashlights, with no end in sight.

Today, we know Ape Cave is actually a lava tube formed by volcanic activity. It’s a popular + unique hiking opportunity, but despite being fully explored, it’s not for the faint of heart.

Quick facts

Starting point: Ape Cave Interpretive Site
Difficulty: Easy to hard
Distance: 3 miles, depending on route
Route type: Out-and-back + loop
Elevation gain: 180 ft or 640 ft with upper cave
Trail surface: Mix of paved/dirt upper trails + subterranean rock
Wheelchair accessible: Paved parking lot, visitor area facilities + trail leading to lower cave entrance; rough terrain everywhere else
Open: May-October
Parking pass/entry fee: Northwest Forest Pass + timed reservation
Dog friendly: No

Brief overview

There are two ways to explore Ape Cave, which was named for the scout troop that first explored it — the St. Helens Apes. Not far from the parking lot, you’ll descend two staircases to the floor of the cave. From here, you choose your adventure: either the easier lower cave route, or the more difficult upper cave journey that includes a scenic, above-ground hike.

The more difficult 1.5-mile upper cave route includes scrambles over large rock piles and a climb up an 8-ft. rock wall. You’ll also come across a “skylight” in the roof of the tunnel, which provides the only glimpse of sunlight since entering. Continue on until you reach a ladder that leads back up to the surface, where you’ll pick up a 1.5-mile above-ground path through shady forest + crusty lava flows to the parking lot.

If spending less time in the pitch black is more your speed, try the easier three-fourths-mile lower cave route. It’s an easy walk, but still not to be missed because it houses a geologic anomaly known as the “meatball.”

Why you should try it

Going outside your comfort zone can be fun, as long as you don’t mind being underground. Plus, you’ll be able to say you’ve explored the third-longest lava tube in North America.

Pro tips

Each person needs to have at least two sources of light (a cell phone doesn’t count) and spare batteries. When open, Ape’s Headquarters offers lantern rentals + information. The lava tunnel is 42° year round, so be sure to pack layers and wear sturdy shoes. Stop in the nearby town of Cougar for lunch or post-hike ice cream.

Let us know

Did you try this hike? Do you know of one we should check out? Send us your thoughts + recommendations.