The lower cave is the easier and more popular route with its fairly level, mudflow-covered floor and unique features such as the "lava ball" wedged in the ceiling. Lower cave is 3/4 miles long. Allow 1 1/4 hours to complete a round trip.

The upper cave is for the more adventurous. This challenging hike climbs over large rock piles, scales an 8-foot lava fall and requires good balance and sturdy shoes. Upper cave is 1 1/4 mile long, but you need to allow 2 1/2 hours for its exploration.

The above-ground Ape Cave Trail (1 mile) will take you back to the main entrance. It's an easy level hike through the forest and also crosses some recent mudflows. Come prepared. Bring two sources of light, sturdy shoes, and warm clothing (even during summer, temperatures are 42 degrees.) Lantern rentals and guided interpretive walks are available during the summer.

Follow I-5 to the WA-503 East exit. Follow this road to FR-90. Take 90 through Cougar to FR-83. Turn left and follow to FR-8303 and the Ape Cave parking area.

Ape Cave is the longest intact lava tube in the continental United States. There are 2 routes through the cave with interpretive signs along the way. An above ground trail completes the loop.