18 of America's great show caves and underground wonders.
Mammoth Cave in Kentucky is the longest known cave system on Earth, with more than 400 miles surveyed and more still being mapped.
Beneath America's surface lies a world of limestone cathedrals, glittering formations, and lava tubes. This is a curated checklist of 18 of the best caves and caverns you can tour, grouped by type, with each one's location and what it's known for — a planner for anyone drawn to the underground.
| Cave | Location | Known For |
|---|---|---|
| Mammoth Cave National Park | Mammoth Cave, KY | Longest in world · 426+ mi surveyed |
| Carlsbad Caverns National Park | Carlsbad, NM | Big Room is largest cave chamber in U.S. |
| Wind Cave National Park | Hot Springs, SD | Box-work formations |
| Jewel Cave National Monument | Custer, SD | 3rd-longest in world |
| Oregon Caves National Monument | Cave Junction, OR | Marble interior |
| Lava Beds National Monument | Tulelake, CA | Lava tube caves |
| Cave | Location | Known For |
|---|---|---|
| Luray Caverns | Luray, VA | Stalacpipe Organ |
| Howe Caverns | Howes Cave, NY | subterranean lake boat ride |
| Ruby Falls (Lookout Mountain) | Chattanooga, TN | 145 ft underground waterfall |
| Meramec Caverns | Sullivan, MO | 7-story formations |
| Cumberland Caverns | McMinnville, TN | Volcano Room concerts |
| Cave | Location | Known For |
|---|---|---|
| Marengo Cave | Marengo, IN | National Natural Landmark |
| Kartchner Caverns State Park | Benson, AZ | most-pristine recent discovery |
| Bluespring Caverns | Bedford, IN | underground river boat tour |
| Sea Lion Caves | Florence, OR | only sea-cave with sea lion colony |
| Cave | Location | Known For |
|---|---|---|
| Ape Cave (Mt. St. Helens NM) | Cougar, WA | Longest lava tube in continental U.S. |
| Volcanoes National Park (Nahuku Lava Tube) | Volcanoes NP, HI | Walk-through lava tube |
| Lava River Cave | Bend, OR | 1 mi long |
Turn this list into a keepsake. The Triptyka Caves & Caverns Passport is a printable PDF with a curated checklist, a detail page for each cave, suggested routes, and achievement badges to earn.
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Bring a jacket; most caves stay around 50–55°F year-round regardless of the weather outside. Book tours ahead, especially at national-park caves like Carlsbad and Mammoth, where popular tours sell out. Never touch the formations — oils from your hands stop them growing. Follow bat-protection rules; many caves ask visitors to walk through decontamination mats to help slow white-nose syndrome, a disease devastating North American bats.
Mammoth Cave in Kentucky is the longest known cave system on Earth, with more than 400 miles surveyed and more still being mapped.
Wear a light jacket and closed, non-slip shoes. Most show caves stay cool — around 50–55°F — all year, and paths can be damp and uneven.
For popular national-park caves like Carlsbad Caverns and Mammoth Cave, yes — guided tours often sell out, especially in summer. Many commercial show caves accept walk-ups.
Oils and dirt from your hands can permanently stop a formation from growing and discolor it. Stalactites and stalagmites grow incredibly slowly, so touching causes lasting damage.
A printable caves and caverns passport — a curated checklist, a detail page for each cave, suggested routes, and achievement badges — makes it easy to mark off each one.