Explore the mysterious lava tubes of Mount St. Helens that were formed during a volcanic eruption 1,900 years ago. Ape Cave was formed when the surface of the lava flow cooled and hardened while molten lava continued to flow far beneath. Ape Cave was discovered in 1951 by Harry Reese and his sons, who named the cave after their outdoor club, the Mount St. Helens Apes. So don’t be disappointed if you don’t see Bigfoot.

©Melissa Farage

Before you begin the hike make sure you have the essentials: two or more sources of light (a lantern plus a headlamp or flashlight), sturdy shoes, water, and enough clothing to keep you comfortable in the 40 degree underground environment. Set off from the Ape Cave Visitors Center, and follow the trail about a quarter of a mile to the Main Cave Entrance. Descend into the gaping cave mouth and light your lantern in the glow of daylight before venturing into the darkness. There are two sections of the cave. The lower cave is .75 miles long each way, and is popular because of its level, sanded floor. On your way through this cave you’ll find marvels such as a large stone, affectionately known as the ‘Meatball,’ wedged in the ceiling and the ‘Railroad Tracks’ gouged deep into the ground. Continue down the cave until it becomes too low to walk. You will have to turn around and retrace your steps to explore the Upper Cave.

©Melissa Farage

Pass beneath the cave’s main entrance to reach the Upper Cave. This portion of the lava tube is much more rugged than the Lower Cave. Hikers are challenged with large rock piles, low ceilings, and tight squeezes through breezy, narrow passages. The Upper Cave tests both your balance and your agility, greeting spelunkers with several vertical lava falls to scramble up. Roughly three-quarters of the way through the 1.2 mile Upper Cave you will find the hopeful glimmer of daylight. The Upper Cave’s Skylight offers visitors a brief view of the terrain above, although it is inaccessible as an exit. Continue through the lava tube to exit at the Upper Entrance. Take the above-ground Ape Cave Trail for 1 mile to reach the Main Cave Entrance and the Ape Cave Visitors Center.

©Melissa Farage

If you’re looking for an adventure and an escape from summer crowds, pack your snowshoes and hike the Ape Cave Trail in spring. Park at USFS 8303 and snowshoe 1.2 miles to the Ape Cave Visitors Center. Call the Mount St Helens Visitors Center for information about weather conditions and road accessibility. Because of limited accessibility in the spring, the popular lava tubes will be empty of tourists, giving you a less crowded experience.



Length: Uper Cave 1.2 miles one way
Length: Lower Cave .75 miles one way
Variety: Lower Cave out and back
Variety: upper Cave Loop
Elevation Gain: Upper Cave 200 ft
Elevation Gain: Lower Cave negligable
Difficulty: Upper Cave dificult
Difficulty:Lower Cave easy
Season: Any
Trail open to: Humans only
Passes Permits: North West forest Pass
Facilities at Trailhead: Ape cave visitor center, bathroom (summer)
Maps: Green Trails No. 364 Mount St. Helens



Driving Directions:

Take Exit 21 from I5. Drive east on Highway 503 and USFS Road 90 for about 35.7 miles to the junction of USFS Roads 83 and 90. Turn left onto USFS Road 83 and continue 2 miles to the junction of USFS Roads 83 and 8303. Turn left onto USFS Road 8303 and continue 1.2 miles to the Ape Cave parking lot.


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