Top 10 Caves in the United States
The United States has exceptional cave diversity: the world's longest mapped cave, the world's most elaborate rare speleothem collection, the densest concentration of volcanic caves in the lower 48 states, and dozens of significant karst systems distributed across limestone-rich regions from Indiana to New Mexico. The National Park Service manages seven major cave parks; the Bureau of Land Management administers hundreds of significant caves across the west. The National Speleological Society's 250-plus grottos provide the main route into wild caving.
All caves here are on the cave map.
1. Mammoth Cave, Kentucky
Karst cave, UNESCO World Heritage Site. Mammoth Cave National Park in central Kentucky contains the longest known cave system in the world at approximately 686 kilometres of mapped passage — a figure that increases with each season's survey. The cave was first explored systematically by an enslaved man named Stephen Bishop in the 1830s and 1840s; Bishop's knowledge of the cave was encyclopaedic and his hand-drawn map of 1842 remained the definitive guide for decades. The park is also an International Biosphere Reserve. Ranger-led tours range from a paved self-guided loop to multi-hour wild cave tours in active passages. Tour grade A to C.
2. Carlsbad Caverns, New Mexico
Karst cave, UNESCO World Heritage Site. Carlsbad Caverns National Park contains the Big Room — at approximately 33,210 square metres the largest cave chamber by floor area accessible to the general public in the US. The cave also contains Lechuguilla Cave (see below) and the famous evening bat flight when hundreds of thousands of Mexican free-tailed bats exit the Natural Entrance. The Big Room self-guided circuit is 1.6 kilometres; ranger-guided tours cover additional sections. Tour grade A.
3. Wind Cave, South Dakota
Karst cave, National Park. Wind Cave in the Black Hills of South Dakota is named for the barometric wind that blows in and out of the cave entrance as atmospheric pressure changes on the surface — a phenomenon caused by the cave's enormous volume relative to its small entrance. Wind Cave contains the world's most extensive known deposits of boxwork, a rare cave formation consisting of calcite fin-blades projecting from walls and ceilings in honeycomb patterns, formed when calcite was deposited in rock fractures and the surrounding limestone dissolved away. Tour grade A to B.
4. Jewel Cave, South Dakota
Karst cave, National Monument. Jewel Cave near Custer in the Black Hills is the third longest cave in the world at approximately 338 kilometres of surveyed passage. The cave was named for the calcite spar crystals lining its walls and discovered in 1900 by Frank and Albert Michaud. The majority of the cave was explored by Herb and Jan Conn over a period of decades beginning in the 1950s — one of American caving's great sustained exploration projects. Tour grade A to C (scenic, historic, and wild cave tours).
5. Lechuguilla Cave, New Mexico
Karst cave (restricted research access). Lechuguilla within Carlsbad Caverns National Park was discovered in its deep extent in 1986 following years of digging at a historically known pit. The cave is approximately 249 kilometres long and 489 metres deep. Its rarity lies in its speleothem assemblage: the cave contains gypsum chandeliers (enormous suspended gypsum crystal formations), sulfuric acid speleothems, pool fingers, cave pearls of exceptional size, and a range of rare minerals found nowhere else. Lechuguilla is accessible only to permitted scientific research teams. Its microbial communities have yielded novel antibiotic compounds of biomedical interest.
6. Kartchner Caverns, Arizona
Karst cave, State Park. Kartchner Caverns is frequently cited as a model of conservation-oriented show cave development. The cave was discovered in 1974 by Gary Tenen and Randy Tufts, who kept the discovery secret for 14 years to protect it from vandalism while working with Arizona State Parks on a management plan. The park opened in 1999 with airlock entry systems to preserve the cave's humidity (the cave is 99% humidity throughout — the formations are actively growing), sensor-controlled visitor management, and stringent guide training. The cave contains the world's longest known cave soda straw stalactite at 2.1 metres. Tour grade A.
7. Caverns of Sonora, Texas
Karst cave. The Caverns of Sonora near Sonora in the Edwards Plateau of Texas are regarded by many American cave scientists as the most beautiful cave in the US for diversity and density of rare speleothems. The cave contains helictites of exceptional form and number, cave coral, aragonite anthodites, cave pearls, and flowstone in chambers whose walls are coated in continuous crystal growth. The cave was discovered in the early twentieth century; the extent of the speleothem formations was revealed to modern visitors from 1955 onward. Tour grade A.
8. Luray Caverns, Virginia
Karst cave. Luray Caverns in the Shenandoah Valley has been continuously open to visitors since its discovery in 1878 by Andrew Campbell and Benton Stebbins. The cave's most famous feature is the Stalacpipe Organ, constructed by Leland Sprinkle beginning in 1954: rubber mallets strike stalactites of different sizes throughout the cave to produce tones, the instrument covering 3.5 acres of cave space — the world's largest musical instrument by some measures. The cave is a National Natural Landmark. Tour grade A.
9. Marengo Cave, Indiana
Karst cave, National Natural Landmark. Marengo Cave in southern Indiana has been a show cave since its discovery in 1883 by schoolchildren Blanche and Orris Hiestand. The cave contains two separate tour circuits — the Crystal Palace route (extensive flowstone) and the Dripstone Trail — through a cave of moderate size but high formation density. Marengo sits at the northern edge of Indiana's Mitchell karst plain, which also contains Wyandotte Cave and several other significant wild and show cave systems. Tour grade A.
10. Howe Caverns, New York
Karst cave. Howe Caverns near Howes Cave in upstate New York has been a commercial show cave since 1843, making it one of the oldest continuously operating show caves in North America. Visitors descend by elevator to the cave level and take a flat-bottomed boat ride on the underground Lake of Venus. The cave was discovered in 1842 by local farmer Lester Howe, who noticed cattle clustering near the cave's natural air vent in summer — the air flowing out of the cave kept flies away, making the spot attractive to livestock. The cave maintains a constant 12°C. Adventure caving tours explore sections beyond the standard circuit. Tour grade A.
Planning a US cave trip
The most concentrated cluster of nationally significant caves is in the Black Hills of South Dakota: Wind Cave and Jewel Cave are approximately 90 kilometres apart, reachable from a Rapid City or Custer base. Mammoth Cave in Kentucky is a standalone destination; the nearest other significant cave is Mammoth Onyx Cave about 40 kilometres away. New Mexico's Carlsbad Caverns and Lechuguilla share a park unit; the drive from Albuquerque is four hours. Arizona's Kartchner Caverns sits near Benson in the Sonoran Desert, accessible from Tucson. The Texas Hill Country anchors Caverns of Sonora and Natural Bridge Caverns within a few hours of San Antonio.
The NSS maintains a cave locator through its grotto network; for access to wild and permitted caves outside the National Park system, contacting the relevant local grotto is the most effective route to finding supervised access to significant non-show caves.