A lot of people have heard of the Ape Cave by Mt. St. Helens, but Falls Creek Cave is its less known and less visited little brother. This lava tube is located in the Gifford Pinchot National Forest about 40 minutes outside the small town of Carson, Washington. The cave is roughly 1.2 miles long.
The entrance to the cave can be tricky to find and is located at the end of the 601 spur near the parking area in the second of a series of three caves. Falls Creek Cave requires a lot of scrambling and climbing of small boulders and is a bit more challenging than Ape Cave.
The caves are not monitored or maintained, so please be very careful while exploring. You'll want to wear sturdy boots, leather gloves, possibly a helmet and headlamp, knee pads and clothing suitable for approximately 40 degrees, year-round.