Go away the rain gear at dwelling: these eight treks happen totally underground.
Mammoth Cave Nationwide Park cavern entrance (Photograph: W. Drew Senter by way of Getty Photographs)
Revealed April 28, 2026 05:05AM
Whereas the overwhelming majority of our nation’s pure wonders exist above floor, a choose few parks, forests, and nationwide monuments characteristic a hidden basement degree. Mammoth Cave Nationwide Park, for instance, sits atop a hole basis: The bottom is perforated with greater than 400 miles of twisting underground passageways. And underneath South Dakota’s Black Hills, you’ll discover Jewel Cave and Wind Cave, which collectively boast 390 miles of corridors.
The difficulty with large cave methods is that they usually include security considerations—like tight constrictions, sudden drop-offs, and labyrinthine floorplans. As such, a few of the nation’s largest caves, together with Wind and Jewel, are virtually totally closed to the general public. Many different caverns have been both privatized or commercialized, limiting guests to brief, Disneyfied loops that provide one thing lower than an actual wilderness expertise.
Happily, there are a couple of caves within the U.S. the place you may discover unsupervised. Others provide guided excursions that do a superb job of protecting issues wild—and nonetheless provide an actual sense of what it’s wish to wind by way of the unexplored bones of the earth.
Subsequent time you’re making an attempt to get away from the crowds, the UV rays—or the world at giant—head to one in every of these nature-made bunkers for just a little subterranean R&R.
Lava Beds Nationwide Monument, CA
When lava runs down a slope, it varieties a rivulet. Whereas the uncovered outer edges of the rivulet rapidly cool and solidify, the middle of the tube continues to circulate till all of the lava has moved downhill. That leaves behind a hole stone tube that resembles a worm casing—or a penne pasta, relying on how appetizing you want your metaphors.
Many volcanic hotspots comprise a couple of of those. However Lava Beds Nationwide Monument accommodates greater than 700. Higher but, you may discover them at no cost. Carry a flashlight or headlamp, a backup, and a helmet, and test in on the customer middle to get a walk-in caving allow. Valentine Cave and Cranium Cave are nice locations to begin.
Carlsbad Caverns Nationwide Park, NM
New Mexico’s Guadalupe Mountains are riddled with historical caves, a few of which started to kind as many as 6 million years in the past. Whereas the biggest of those—the 140-mile-long Lechuguilla Cave—is closed to guests, you may discover a big chunk of the system all by yourself. Just a few completely different trails prolong all through the cave community. For a extra easy-going romp, goal the 1.25-mile Large Room path. For severe elevation achieve, take the scenic route: The Pure Entrance Path rises greater than 750 ft over simply 1.25 miles.
Observe: Earlier than and after you enter the cave, be sure you clear your sneakers on the offered mats. This protects the cave’s 400,000-strong bat inhabitants from invasive fungi and micro organism.
Coconino Lava River Cave, AZ
About 700,000 years in the past, a river of volcanic ooze inched throughout Northern Arizona, abandoning a mile-long tube of hardened lava. At present, you may journey by way of the within of the tube, dubbed the Coconino Lava River Cave after its location within the modern-day Coconino Nationwide Forest. The hall is dozens of ft excessive in locations and pocked with ragged holes that allow in shafts of daylight from the world above. Carry a backup gentle supply and loads of layers; the inside of the tube stays a gradual 35 to 45°F year-round.
Blue Ridge Tunnel, VA
Constructed by an engineer who served in Napoleon’s military earlier than immigrating to the U.S., the Claudius Crozet Blue Ridge Tunnel was one of many longest railroad tunnels on this planet on the time of its 1858 completion. And whereas it’s the one man-made characteristic on this listing, it’s as worthy an journey as every other. Whereas the practice tracks have lengthy been eliminated, the 0.8-mile tunnel stays, burrowing beneath 2,415-foot Mt. Afton in Virginia. To entry it, park alongside the Blue Ridge Parkway on the East Trailhead close to Afton, which delivers you to the tunnel mouth after only a half-mile method on a simple, crushed-gravel path.
Mammoth Cave Nationwide Park, KY
Not a lot a single cavern as a 400-mile tangle of underground passageways, Mammoth Cave is likely one of the largest cave methods on this planet. Unsurprisingly, a spot this huge has its personal ecology: It’s dwelling to 5 varieties of bats, blind fish, and a uncommon crustacean known as the Kentucky cave shrimp. Whereas unguided visits are off-limits right here, the park affords two pretty adventurous excursions by way of its less-trafficked corridors: a two-mile intro-to-caving tour (on provide by way of Could 15), and a 2.5-mile River Styx tour which takes guests to an underground river and a characteristic aptly dubbed “The Bottomless Pit.”
Ape Cave Lava Tube, WA
At 2.5 miles, the Ape Cave Lava Tube is the third-longest in North America—and affords an eerie glimpse underneath the hood of Mt. St. Helens. Two completely different trails wander by way of the cavern: the paved and accessible Decrease Cave Path, which is simply shy of a mile, and the 1.5-mile Higher Cave Path, which options some gentle scrambling and a extra concerned journey into the depths of the mountain. Take into account that advance reservations are required, and also you’ll must carry your individual gentle supply and backup. Ape Headquarters rents lanterns, however a superb headlamp can even do the trick.
Kaumana Lava Tubes, HI
Buried within the piled jungle foliage of Kaumana Caves State Park, you’ll discover a remnant of the island’s volcanic previous: a 2-mile-long lava tube, which was shaped when Mauna Loa erupted in 1881. To get there, descend a half mile of stairs by way of layers of palms and ferns to achieve the forest ground. Then the path descends into the tube by way of a large skylight and splits. Go left for some gentle scrambling and a extra rugged expertise, or proper for a kid-friendly trek. Carry a pair of sunshine sources and a pair of grippy sneakers; the cave ground will be slick, and there’s no synthetic lighting.
Crystal Cave, CA
This ethereal underground palace is likely one of the hottest corners of Sequoia and Kings Canyon Nationwide Park—and for good motive. A 0.5-mile method carries guests up steep singletrack earlier than delivering them right into a yawning hole within the moss-covered cliff. That is your beginning line to the long-lasting Crystal Cave.
When you do need to pay for a tour and go along with a information, the park does a superb job of limiting the variety of guests, and the trail feels just a little wilder than some. Wind by way of stalactites, stalagmites, and chandeliers of suspended crystal on this 0.5-mile loop.
