Ape Cave

Record

Why it matters

The longest lava tube in the continental United States, formed by an eruption roughly two millennia ago beneath what is now Mount St. Helens country.

Field note

This is a true underground route with no installed lighting. Seasonal access uses timed reservations to protect the cave and control congestion.

Access

How to approach it lawfully

Access status

Reservation required. Advance reservation or timed entry is required. Recorded as: Seasonal, timed entry.

Reservation

Required. See the official source.

Seasonality

Seasonal or schedule-dependent. Check the current season and hours before traveling.

Practical details last checked July 2026. Conditions change. Check the primary source before leaving home.

Plan the stop

What to plan for

Time

1 to 4 hours

Cost

Reservation and recreation pass (Fee or pass)

Terrain

Cold, pitch-dark, rough cave floor.

Mobility

Rough underground route with no installed lighting.

Parking

Not recorded in this file. Check the official source.

Weather

Not recorded in this file. Check the official source.

Directions to the public entrance ↗Opens Google Maps with these coordinates. The provider sees them under its own privacy policy. Confirm the entrance against the official source first.

Record

Sources

• Primary sourceUS Forest Service ↗, opens in a new tabGovernment source · fs.usda.gov · accessed 2026-07

Sources are summarized in the Atlas's own words and checked on the dates shown. See the methodology, or send a correction.