National Park Service, Oregon.
Deep within the Siskiyou Mountains are dark, twisting passages that await your discovery. Eons of acidic water seeping into marble rock created and decorated the wondrous “Marble Halls of Oregon.” Join a tour, get a taste of what caving is all about, and explore a mountain from the inside and out!
Take 199 to Cave Junction, Oregon. Turn onto OR-46 (a Chevron gas station is on the corner). Follow OR-46 for 20 miles to the Monument and Preserve.