Ape Cave

Explore the Depths of Ape Cave

Ape Cave is a fascinating lava tube located on the southern flank of Mount St. Helens. Formed approximately 2,000 years ago during a volcanic eruption, it is the longest continuous lava tube in the continental United States. Visitors can explore two main sections: the easier Lower Cave and the more challenging Upper Cave.

Lower Cave

• Length: 0.75 miles round trip
• Difficulty: Easy
• Features: Smooth floor, minimal obstacles

Upper Cave

• Length: 1.5 miles round trip
• Difficulty: Hard
• Features: Rock piles, an 8-foot lava fall, and a rougher terrain

Prepare for a unique adventure as you navigate through the dark, cool environment of the cave. Remember to bring a flashlight or headlamp, as the cave is unlit, and wear sturdy shoes to handle the rocky terrain. The temperature inside the cave remains a constant 42°F (5.5°C) year-round, so dress warmly.

Planning Your Visit

Ape Cave is open year-round, but the best time to visit is from May to October when the weather is more favorable. The trailhead is equipped with a parking area, restrooms, and an information kiosk. Be sure to check for any seasonal closures or restrictions before your visit, as conditions can change rapidly in this volcanic region.