Ape Caves Lava Tubes is one of the most unique trails you can hike in Washington State. As one of the longest lava tubes in the United States, you can expect unique rock formations, moderate scrambling, and pitch darkness!

Ape Caves was on my list of “want to do” trails in Washington for years before I finally committed myself to the three-hour drive to the trailhead near Cougar, WA. My only regret? Waiting so long!

In this blog post, I will share everything you need to know about the two trail options you have within the lava tube, recommended gear for your trip, and securing permits. If that sounds good to you, let’s get into it!

Why this blog? Hi! My name is Sarah Borgen, and I am a full-time educator and part-time adventurer. I love using my free time to explore Washington and have been since 2018. I’ve been sharing my favorite spots in Washington on my Washington Map, which has over 400 destinations, trails, campsites, and so much more! Check it out here.

Just a heads up! This post contains affiliate links which means I could earn a small commission on purchases made through this site at no additional cost to you. I appreciate your support!

Comprehensive Guide to Washington’s Ape Caves near Mount St. Helens

Why Ape Caves? When I first heard of Ape Caves, I was immediately drawn to the thought that Washington had a cave system. What exactly that cave system was, I had no idea. But I remember driving past the sign to Ape Caves on my way to the Climbers Bivouac, the trailhead for summitting Mount St. Helens. I made a mental note of where Ape Caves was, so I could come back to it at a later date!

After knowing that the Ape Caves existed but having no idea where they were, finally being able to put them on the map motivated me to plan another trip down there.

Walking up to the entrance of Ape Caves, you would have no idea that just below your feet is an almost two-mile-long cave system.

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Quick Planning Guide for Ape Caves

Use this short planning guide to get started on your Ape Caves trip!

• Where is Ape Caves Located? Ape Cave is located near Cougar, in Southwest Washington.
• When to visit?: You can visit Ape Caves year-round, but I would recommend visiting in late spring and early summer so you can experience the wildflowers that bloom around Mt. St. Helens and cooler temperatures.
• Time Commitment: To complete the upper caves, you will need 2+ hours.
• Trip Length: If you’re planning a trip to the area, two nights would be sufficient to complete the popular trails.
• Permits: To complete the Ape Caves, you must reserve a $2 parking permit on Recreation.gov prior to your trip.
• Temperature: The caves remain at 42°F (5.6°C) year-round regardless of outside conditions. Dress for the cave temperature, and whatever the temperature is outside.
• Where to stay? You can find cute vacation rentals here or camp at one of the many campground options in the area.

If you have more questions about planning your trip to Ape Caves, feel free to leave them in the comments! I’d be happy to help answer any questions.

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Packing List for Ape Caves

Hiking the Ape Caves trail requires similar gear to any other trail; however, you’ll need a few more pieces of safety equipment to ensure your safety through the cave system. Remember, no cave trip is truly safe.

Here is a short list of recommended gear for your cave trek!

• Sturdy Hiking Boots or Close-Toed Shoes—I have been using Oboz Bridgers for four years now and love them. You can definitely hike this trail in trail runners or sneakers, but sandals are not recommended.
• Long Pants – I wore leggings, but there are points on the trail that require tight squeezes and butt scooting across rock. Long pants can protect your legs!
• Light Jacket – The cave is always 42°F, so you’ll want to bring a light jacket. I wore my Arc’teryx Atom Hoodie, and it was perfect for cool temperatures and working up a sweat.
• Head Lamp – A head lamp is a must for the trail. The Black Diamond Spot is my favorite headlamp because it is lightweight and rechargeable.
• Secondary Light Source – Pack a small flashlight if your headlamp battery dies. Your phone flashlight does not count as a secondary light source. Two sources of light are a gear requirement for the trail. I brought the Black Diamond Moji as my alternative light source.
• Water – There are no viable water sources on the trail. Pack enough water for a safe trek through the cave and back on the return trail. Two liters are sufficient.
• Gloves – Gloves are optional but helpful for some of the more technical rock scrambles and rope climbs. Some of the rocks in the cave can be tough on your hands.

NOTE: No food or drinks(except water) are allowed inside Ape Cave.

Have questions about what to bring? Let me know in the comments and I would be happy to help!

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Passes & Permits for Ape Caves

Before you get to the trailhead for Ape Caves, you will need two different permits/passes.

1. Ape Cave Interpretive Site Ticket: This is a $2 parking pass you’ll need to purchase. It is timed-entry so when you purchase your ticket, you need to register for a specific date and entrance time. You must show up at the beginning of your time window or you could be denied entrance. Purchase your ticket here.
2. Park Pass: You can use an America the Beautiful Pass or a Northwest Forest Pass at this location.
   • An America the Beautiful Pass is an annual pass that provides access to all National Parks, Forests, and Monuments. It costs $80 annually.
   • The Northwest Forest Pass is another annual pass that provides access to all National Forests in Washington and Oregon. It costs $30 annually.
   • Day Passes are available for $5 on-site. If you do not plan on visiting other National Parks or Forests during the course of a year, a day pass is another excellent option.

Ape Cave is located inside Mount St. Helens National Volcanic Monument, so if you plan on visiting multiple National Parks throughout the year, the cost of the annual pass is typically paid off after three visits. I purchase one every year.

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What is Ape Cave?

Ape Cave is the third-longest lava tube in the world, located just outside of Gifford Pinchot National Forest. This pitch black underground tunnel has been a popular attraction since its discovery in 1947 and later exploration in the 1950s by a boy scout group.

The Boy Scout group honored their sponsor, the St. Helens Apes, by naming the area Ape Caves.

The cave system is a Lava Tube formed at the southern flank of Mount St. Helens.

The Ape Cave Lava Tube formed over 2,000 years ago. As the molten lava passed through the tube it heated the interior rock of the tube and as it cool it created Cave Basalt which you can see as you walk through.

According to the St. Helens Guidebook by Vulcanospeleology Group, Ape Cave is 3,400 meters long with a maximum height of 11.6 meters and a maximum width of 12.2 meters.

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Getting to Ape Cave

The Ape Cave parking lot is on Forest Service Road 8303, 9 miles outside Cougar, WA.

Check forest road conditions prior to driving to the trailhead. Road construction in the area is common, and a long detour may be required.

The Ape Caves parking lot has about 50 spots (some are roped off), including spots for RVs and Buses. Four pit toilets with hand sanitizer are available, and there is a visitor center, Ape Headquarters Center.

Ape Headquarters Center

Discover Your Northwest operates The Ape Headquarters, which has varying visitor hours. The center offers lantern rentals, snacks for sale, and a small gift shop.

You can call for updated hours by calling 360-449-7800.

Related Read: Summitting Mount St Helens Trail Guide

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Hiking Ape Caves

There are two options for the type of experience you have in the cavern. You can do the upper cave or the lower cave.

Hiking Upper Ape Caves

I chose the upper cave route because it provided a more immersive experience of the lava tube. I was prepared to hike over boulder piles, scramble up an eighth-foot rock wall, and travel through total darkness.

I was not prepared for the unevenness of the lava tube floor. I actually thought to myself a number of times on my adventure that the floor of the cave was a tripping hazard, and anyone without great balance would struggle. Hence, the need for sturdy shoes.

Starting the Hike

You will see a line of boot brushes when you reach the trailhead entrance, to the right of the Visitor Center. You must clean your shoes with these boot brushes before and after completing the hike. This is to protect the delicate cave ecosystem and eradicate the transfer of white-nose syndrome to the bat population in the cave.

The cave does have a bat population; however, I did not see any on my trip. Unfortunately.

Paved Trail

To get to the entrance of the cave, you will do an easy walk on a paved trail. Here you will find informational signs about the cave system and Mount St. Helens put together by the U.S. Forest Service.

At the end of the Paved Trail is the entrance of the cave.

Typically, there are U.S. Forest Service employees around who can answer any of your questions about the cave.

Cave Entrance

The cave entrance is essentially a large hole in the ground. Follow the rock stairs down to the metal gate marking the entrance.

I recommend taking some time here before starting your underground hike because of how beautiful this cave entrance is.

The plants surrounding the cave entrance include ferns, bear grass, and fireweed.

Immediately after entering the cave, you will need your light source.

Upper vs. Lower Ape Cave

After walking through the main entrance of the cave, you will go down a collection of metal stairs, where you will see a sign indicating the direction of the different cave routes.

If you continue straight past the stairs, you will come across another set of stairs leading to the lower Ape Cave. This is considered the easy route and accessible for small children.

If you walk in the opposite direction of the stairs, you will begin the Upper Cave Route. The upper cave route is more challenging and requires navigation over large rock piles.

Beginning Upper Ape Cave

You will find uneven footing immediately after beginning your hike on the Upper Ape Cave route. The grooved floor of the cave is easy to trip on and roll your ankle. Take precautions to check the cave floor as you walk to avoid tripping.

Shortly after starting this section of the trail, you will come across the first and largest rock pile in the cave. After navigating this rock pile, it is important to consider how challenging that was and if you can do that another six times. If you think that was too challenging or unpleasant, turn around.

Many of these rock scrambles include low ceilings. Be careful not to bump your head on a protruding rock as you pull yourself over boulders.

Lava Fall

The first half of the underground portion of the trail is a collection of small boulder fields and large caverns.

That is, until you get about 0.8 miles in when you reach the most challenging part of the trek. Here you will reach the narrowest portion of the trail, about 2 feet wide.

This narrow portion includes a slick lava fall and a smooth wall with limited handholds. There is a rope for you to hold onto, but after seeing how it was secured, I don’t have much faith in the rope’s integrity. There is one foothold for you to push off of. Here, you will grab onto the sides of the cave wall for purchase.

This section requires upper body strength and many people need someone to give them a boost to get up and over the lava fall.

I completed Ape Cave solo and struggled a little bit at this section, but was able to get up. However, anyone shorter than 5 feet might struggle to reach many of the handholds on their own.

Read Next: Tips for Solo Backpacking

Skylight

The skylight is one of my favorite parts of the trail. The little amount of light that is able to pass into the cave is enough for plants to grow around the opening.

I found myself taking my time here to enjoy the beauty of the Skylight.

This is not an entrance or an exit. You will need to continue another quarter mile to get to the exit of the cave.

Metal Ladder Exit

When you reach the metal ladder, you have reached the end of the cave. This metal ladder is a little worse for wear, and many rungs have significant rust. Some of the handholds have been wrapped in duct tape while others are degraded with rust.

Climb up the ladder, but be careful not to bump your head due to the low head clearance.

The area surrounding the cave exit is beautiful, and you can really appreciate the unique geology of the Mt. St. Helens area here. The ashy soil and high desert ecosystem are truly beautiful.

Hiking Back to the Trailhead

The trail back to the parking lot is easy to follow through a shady forest. The route is marked with blue diamonds, making route finding easier during the winter months.

Going from 46 degrees F in the cave to the outside temperature is an interesting feeling! I had really grown to enjoy the cave’s cool temperatures.

It is primarily a gentle descent back to the trailhead.

When you make it back to the trailhead, don’t forget to brush your shoes off again!

Check out Washington’s Best Hikes Here

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Ape Cave FAQ

Here are some frequently asked questions about the Ape Cave in Washington State.

Have a question that is not answered here? Let me know in the comments!

How long does it take to walk through the Ape Caves?

To complete the upper caves trail, plan on about two hours minimum. This includes the short trail to the mouth of the cave, through the old lava tube, and hiking back on the dirt trail.

The upper cave is the more interesting route, so you may find yourself taking longer within the cave to explore and examine it. Anticipate the rugged miles of the cave taking longer than your typical mile time.

The lower cave route can be completed in an hour or less.

Do the Ape Caves cost money?

Yes! Ape Caves costs money to park in the parking lot. There is a $2 reservation fee on Recreation.gov for securing a parking spot.

You will also need an America the Beautiful Pass or a Northwest Forest Pass.

Why do they call them Ape Caves?

The Ape Caves were named after the St. Helens Apes, the sponsor of a local Boy Scout Troop that explored the caves in the late 1950’s.

The St. Helens Apes’ name was inspired by the “brush apes,” aka Bigfoot.

How to dress for the Ape Caves?

The temperature of the long lava tube is 46 Degrees Fahrenheit year-round.

You will want to wear a light jacket while inside the cave.

You will also need a head lamp, extra batteries, sturdy shoes, long pants, and water.

Read Next: Summer Guide to Leavenworth, WA

Is the Ape Cave trail hard?

Yes and no. The Ape Cave trail is not very difficult in distance or elevation gain; however, hiking through the lava tube poses other challenges, like low visibility and scrambling.

Getting used to hiking with a headlamp in total darkness is a challenge. You will be moving your head around constantly to make sure you don’t trip, bump your head, or run into a wall. In addition to making sure you’re safe in the dark, you will also want to stop and enjoy the cave views.

Scrambling is a challenge and if you don’t have much experience with hiking along uneven ground, walking through the cave will certainly be challenging. Climbing up large boulder fields is tiring for your arms and legs. You will find that gloves will come in more handy than hiking poles here.

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Pack it up

Ape Caves is located on the south side of Mt. St. Helens and is truly one of the most unique experiences you can have in the area. The short hike through the tunnel is filled with geologic anomalies like a sky light, cave slime, and boulder fields.

Hiking through the cave does require significant effort so analyze the physical ability of the people in your party before committing to completing the Upper Cave. The narrowest part of the passage can be sufficating and hard to squeeze through. The 8-foot lava flow is slightly terrifying to get up and over.

However, for all of the challenges of the cave, it is well worth the blood, sweat, and tears of the journey.

You will not have cell phone service inside the cave, and the flashlight on your cell phone is not advised as primary or secondary light sources.

Have questions? Drop them in the comments and I would be happy to help!