Our last day in Washington was spent on an unusual adventure! We traded sunshine for shadows and went deep underground for an unforgettable experience. Exploring one of Washington’s most fascinating geological wonders — the Mt St Helens Ape Caves! If you’re looking for an adventure that’s equal parts eerie, exciting, and educational, this Washington lava tube is the perfect destination!
You Don't Want to Miss This Family Adventure!
Experience the Ape Caves via a Tour!
What Are the Mt St Helens Ape Caves?
The Ape Caves were formed nearly 2,000 years ago when lava flowed from Mount St. Helens during a quiet eruption. Instead of spewing ash and fire into the air, the lava flowed like a river beneath a hardened surface. It eventually draining out and leaving behind a long, hollow tube. Today, the Mt St Helens Ape Caves are one of the longest lava tubes in Washington, stretching for over two miles beneath the earth.
Getting to the Mt St Helens Ape Caves
Located on the south side of Mount St. Helens, the Ape Caves are a short drive from Cougar, Washington. The route up winds through dense, lush forests, hinting at the wild terrain and volcanic history you’re about to step into. As we approached the parking area, the we were all buzzing with excitement — and maybe a little nervous energy.
Adventuring Into the Darkness
Armed with headlamps, gloves, and a couple of flashlights each, we began our descent into the Upper Cave Section. Our girls are experienced hikers and love a physical adventure. So, we decided to try our hand at the upper section.
There is also a lower section, which is the easier of the two and ideal for smaller children. Here, the floor is relatively flat, and the wide walls make it feel a bit like walking through a rocky subway tunnel.
As we descended into the darkness, the girls were thrilled! They were shouting echoes, spotting odd rock formations, and marveling at the cool air. There was no one around us for the majority of our hike.
About a mile in, we turned off our lights for a moment to experience total darkness. It was a surreal, humbling moment, surrounded by ancient volcanic rock, feeling the silence press in from all sides.
The Upper Cave: A True Underground Adventure
The Upper Cave offers a much more rugged experience. Scrambling over boulder piles and climbing an 8-foot lava wall is part of the fun — and challenge. While the Lower Cave is great for beginners and younger kids, the Upper Cave is where the real adventure begins. It’s a rugged, challenging, and utterly thrilling stretch of the Mt St Helens Ape Caves. It is perfect for anyone looking to test their footing and sense of adventure!
Here’s what makes the Upper Cave so exciting:
1. The Lava Wall Climb
About 0.75 miles into the Upper Cave, you’ll come to what’s arguably the most famous feature: an 8-foot vertical lava wall. There are footholds carved out, and while it’s doable without ropes, it definitely requires some upper body strength and a bit of confidence. Buttercup had no problem scaling the wall by herself, but we had to help Spider Monkey.
2. Rugged Terrain
Unlike the smooth, walkable path in the Lower Cave, the Upper Cave is filled with boulder piles, narrow passageways, and uneven floors. It feels more like navigating an underground obstacle course than a hike. You’ll be ducking under low-hanging rock, scrambling over lava formations, and sometimes even crawling to get through tight squeezes.
3. Lava Sculptures and Volcanic Oddities
One of the coolest things about the Upper Cave is that it hasn’t been as heavily traveled, so the rock features are more dramatic and preserved. You’ll see “lava benches,” where the molten rock once flowed at different heights, and strange drip-like formations frozen in time. It’s like walking through a gallery of natural sculptures created by fire and time.
4. A True Sense of Isolation
Because the terrain is tougher, the Upper Cave is quieter. The deeper you go, the more you feel like an underground explorer charting unknown territory. The silence is almost complete, broken only by the occasional drip of water or crunch of gravel under your boots. It’s equal parts spooky and spectacular.
5. The Exit (or Return)
The Upper Cave ends about 1.5 miles in at a collapsed section of the tube. My recommendation … do the hike backwards!! Start at the exit and hike to the start. Either way, it’s a workout — but totally worth it.
The Lower Cave: Family-Friendly Exploration
If the Upper Cave is the wild side of the Mt St Helens Ape Caves, the Lower Cave is its gentler, more accessible sibling. It’s absolutely perfect for families, or anyone who wants to experience the magic of a Washington lava tube without too much scrambling or climbing.
Here’s what makes the Lower Cave so perfect:
1. A Walk Through Time
The Lower Cave stretches about 0.75 miles one way and offers a fascinating walk through ancient volcanic history. The walls are smooth in places, rippled in others — a visual reminder of the lava that once roared through here thousands of years ago. It’s like stepping inside a frozen lava river. You can actually see the “lava drip” textures along the ceiling and sides, looking like waves or melted candle wax.
2. Flat, Wide, and Manageable
This section of the cave is relatively flat, with wide passages and few major obstacles, making it great for young kids, grandparents, or anyone who’s not up for a big climb. You’ll still need to watch your step because the ground can be uneven and occasionally damp. But, there’s no crawling or climbing required.
With good footwear and a solid flashlight (headlamps = lifesavers), it’s a comfortable and totally surreal hike. Even younger kids can do it with some supervision, and they’ll love the sense of adventure that comes with exploring in the dark.
3. Pitch-Black Fun
One of the coolest parts? The total darkness. About halfway in, we turned off our lights just to feel the true stillness of the cave. It’s unlike anything else — no light, no sound, just the ancient Earth all around you. A little spooky, yes, but also kind of magical. Definitely a core memory.
4. Turnaround or Loop?
Once you reach the end, there’s a small sign marking the turnaround point. Some folks linger here for photos or a snack before heading back out the same way. The round trip takes about an hour, but give yourself extra time if you’ve got curious kids who want to explore every nook and cranny.
Tips for Visiting the Mt St Helens Ape Caves
- Bring your own light sources. At least two per person — it’s pitch black inside! We used these headlamps, lanterns, and flashlights.
- Dress warmly. The caves stay around 42°F year-round.
- Sturdy shoes are a must. The rocks can be slick and uneven.
- Wear leather gloves to protect your hands.
- Check for cave conditions and permits on the Forest Service website. The Forest Service sometimes requires a reservation or timed entry. We needed a timed entry when we visited in late July.
The Family Verdict
Exploring the Mt St Helens Ape Caves was unlike any other family adventures we’ve done. There’s something magical about venturing into the Earth, walking where lava once flowed, and experiencing geology hands-on. It’s the kind of adventure that gets kids asking questions and sparks a sense of wonder in adults too.
So if you’re looking to add a bit of mystery, history, and adrenaline to your next trip, don’t miss this unique Washington lava tube. Just don’t forget your flashlight — and maybe a snack for after you emerge from the depths.
Make sure to check out our adventures in nearby Mount Rainier National Park, Olympic National Park, North Cascades National Park, the Oregon Coast and Crater Lake National Park. Also, follow along on our road trip through the Pacific Northwest!
Follow along on our other amazing family travel adventures at www.adventureisinoursouls.com.
Recommended Supplies
Don’t miss out on these recommended supplies for your family adventure!
For Packing:
For the Airport / Airplane:
Basics:
Outdoors:
- Pocket Binoculars
- Travel Umbrella
- Adult Hiking Hydration Backpack
- Kid’s Hiking Hydration Backpack
- Water Bladder Cleaning Tablets
- Microfiber Towels
- Women’s All Around Jacket
- Women’s Water-Resistant Hiking Pants, These and These
- Women’s Quick Dry Pants and These
- Women’s Quick Dry Shirts
- Women’s Long Sleeve UV Rash Guard
- Women’s Hiking Socks
- Women’s Rain Jacket
- Kid’s Quick Dry Pants
- Kid’s Quick Dry Shorts
- Kid’s Quick Dry Shirts
- Kid’s Long Sleeve UV Rash Guard
- Kid’s Hiking Socks and These
- Kids Rain Jacket
- Kid’s Rain Pants
- Foldable Kid’s Hat
- Men’s Rain Jacket
