15 Largest Caverns in the USA

By Seema Nande on Oct 28, 2016
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With 39 states out of 50 states home to a plethora of caves, USA sure is abundant with these terrestrial wonders. A sheer delight that these caves are, they won’t cease to marvel you with the way they were formed. A result of the Earth’s constant shifting through millions of years, these natural wonders are filled with gravity -defying formations. Statistically, there are over 17,000 caverns in the nation, according to the US Geological Survey. Here, we bring you a list of the largest caverns in the USA! These, over time, became popular tourist attractions to behold Mother Nature’s wonders. Earth’s very own basement, these caves are the perfect place to chill, literally, as you bask in some super cool sights of miles of rock formations, underground pools, and marble pillars!

1. Mammoth Cave

PC:flickr.com/Margaret River

If you have been wondering, where is the world's longest cave located? This is it!

Located in Kentucky's Green River Valley, these impressive-sounding caves absolutely live up to the hype about them. The largest known cave network in the entire world, these caves span over a whopping 285 miles of surveyed cave passageways. Spelunkers, rejoice, this one place that will quench your spelunking thirst like no other! How deep is the Mammoth Cave? It's 379 feet (118 meters)!!!!

Explore the vast chambers and complex labyrinths, climb up hundreds of stairs and steep hills, and for the more adventurous types - take "wild" tours where you explore muddy crawls and dusty tunnels! The famous "Bottomless Pit" is something you must look out for here.

Beautiful vistas of the cave’s natural features include gorgeous gypsum flowers, delicate gypsum needles and rare mirabilite flowers, which are actually minerals shaped like blossoms. Mammoth Cave tours offer a good assortment of the cave tours, ranging from one half an hour up to five or six hours. There is a new discovery happening here, every day!

Mammoth Cave timings - Open throughout the year


2. Sistema Sac Actun


Situated a little away from the Mexican village of Tulum, the Sistema Sac Actun cavern is not only one of the largest caverns in the USA but also the second-longest known underwater cave system in the world! Literally translating to White Cave System, the cavern is situated along the Caribbean coast of the Yucatán Peninsula. To explore this, the easiest accessibility is through the Gran Cenote a hugely popular destination for snorkelers and scuba divers. What draws visitors to the cavern, however, is the cenote, or sinkhole. One of the hundreds that dot the expansive cave system, the cenote will amaze you!

Sistema Sac Actun timings - Open throughout the year

3. Jewel Cave

One of the best caverns in the USA, the Jewel Cave’s navigated passageways stretch a little over 157 miles! This is the third longest known cave system in the world, after the Mammoth and Sistema Sac Actun caves. Located in South Dakota near the town of Custer in the southwest corner of the state, the Jewel Cave has strong winds blowing through the cave given the constantly-changing barometric pressure at the entrance. This airflow is also one reason for much of the cave remains lying undiscovered.

The name of the cavern is derived from unusual cave formations of delicate gypsum strands and sparkling calcite crystals that look like jewels! The caves were designated a national monument in 1908 by President Theodore Roosevelt.

Jewel Cave timings - Open throughout the year, except December 25 and January 1

Check out other most amazingCaves in the world

4. Carlsbad Caverns

One of the best caverns in the USA, Carlsbad Caverns are also popularly referred to as the "Grand Canyon with a roof on it"! Located in the Chihuahuan Desert, these caves are one of the world’s deepest, biggest and most decorated caverns ever found! Stretching for miles, there is something to suit all likes and budgets here. The caves are especially remarkable given the opportunity to explore the undersea world that used to be New Mexico! Sights of prehistoric sea walls sitting next to cacti and other desert shrubs in these caverns that formed when sulfuric acid devoured the limestone are a common sight here. While here, explore the main draw the Big Cave and it's Big Room that spans over a massive 14-acre space filled with unusual calcium-carbonate cave formations. The Bottomless Pit, Giant Dome, Rock of Ages and Painted Grotto formations created when sulfuric acid dissolved the surrounding limestone, are some of the must-see parts open for public tours.

Ranger tours to get down and dirty and crawl through some of the lesser-explored 119 caves are available too.

Carlsbad Caverns timings - Open every day of the year, except Christmas Day

5. Ohio Caverns


Boasting of very unique formation, the Ohio Caverns, are indeed nature’s wonder. Not surprisingly, they are also Ohio’s most popular attractions. Unique and particularly characteristic you will not find similar formations, anywhere else. There are two different routes towards the cavern, that tours guide you by - the historic tour route and the regular route. Spread across 35 acres, this is the perfect family entertainment place for those seeking a little adventure. Various tours are available for various kinds of visitors, amateurs and experts alike. Get ready to be amazed by the most colorful crystal in the US and the gigantic size of this gem!

Ohio Caverns timings - Open throughout the year

6. Mystic Caverns & Crystal Dome Caverns

Having more formations than any other cave in Arkansas' rather impressive collection, the Mystic caverns is located in Harrison. Referred to as many other referrals, these caves are also popular as Twin Caves and the Mansion Cave. For being 400 feet apart from each other and having many giant rooms respectively. The cavern is also home to the "pipe organ," a circular rock formation that looks like it could be used to introduce Count Dracula! A visit here is ought to be a once-in-a-lifetime caving adventure. You will also hear the infamous story of the "spider monkey" while on one of the many guided tours here. The Crystal Dome is what you must see, with its spectacular eight-story dome.

Mystic Caverns & Crystal Dome Caverns timings - Open Monday through Saturday

7. Natural Bridge Caverns

211 feet underground, the Natural Bridge Caverns are the largest caverns in Texas located near San Antonio. An active and growing cavern system, exploring these you will be mesmerized by the waxy texture of the underground formations, caused by the water flow here. The cavern tours also provide spectacular views of wide ranged cave formations and stunning underground chambers such as the Castle of the White Giants and the Hall of the Mountain King. The caves are also home to the world’s largest bat colony!

Natural Bridge Caverns timings - Open throughout the year, except Thanksgiving Day, Christmas day, and New Year’s Day

8. Niagara Cave

PC:flickr.com/Bruce Guenter

Voted as one of the Top 10 caves in the US by several media outlets, the Niagara Cave boasts of huge stalactites, calcite flowstones, and fossils that are over 400 million years old. Deriving its name from the 60 feet waterfall inside, the cave is abundant with hikes and trails, gemstones and a 10-acre picnic area. While the Paul Bunyan's Bed and the Battleship, are great, the wedding chapel inside takes the wow, with over 400 wedding ceremonies performed in it! Explore the caves as you walk through an underground stream carving the passageways in this cavern, an experience certainly un-parallelable!

Niagara Cave timings - Open throughout the year except October 31st. Open in November, weather-permitting. December to April, only weekends, weather-permitting

9. Wind Cave

One of America’s oldest national parks, the Wind Cave National park is home to some of the largest caverns in the USA. Located north of Hot Springs in South Dakota, the Wind Caves derived its name owing to the strong barometric winds at its entrance. The cavern’s complex, maze-like passageways extend more over 136 miles, making it the fifth-longest cave in the world. The outstanding natural display of box work, thin blades of calcite that resemble a honeycomb, will take you aback and how! To protect the caverns here, President Roosevelt created Wind Cave National Park in 1903. You will find rich wildlife around the caverns, Bison and elks being the most common sites.

Wind Cave timings - Open throughout the year

10. Caverns of Sonora

PC:flickr.com/Woody Hibbard

The most active caves in the world, Caverns of Sonora are located about halfway between San Antonio and Big Bend National Park. Interestingly, more than 95% of the formations are still growing. Stretching at 20,000 feet in length and going 150 feet deep, the cavern was formed in 100 million-year-old limestone and is best known for the hundreds of pink and rose-colored stalagmites and stalactites that make it one of the world’s most beautiful caves. Outdoor lovers have some great things to do here, like camping in a tent or even an RV! Do not leave until you get your hands on some fresh cream and butter fudge made at the caverns!

Caverns of Sonora timings - Open throughout the year

11. Luray Caverns


Virginia’s Luray Caverns have more than one and a half million visitors, drawing to it to bask in the wonders of this subterranean wonderland! With cathedral-sized rooms, the cavern is located in the Shenandoah Valley. Towering stone columns formed over millions of years ago by underground rivers and acid-bearing water cutting through the limestone and clay, will overshadow you as if in a thriller movie. The real gem of Luray Cavern - the aptly named Great Stalacpipe Organ, will make for apt haunting sound effects! These are also US’ third-most visited caves. which you must see!

Luray Caverns timings - Open throughout the year

12. Meramec Caverns

PC:flickr.com/Tydence Davis

Located in Missouri near St. Louis, the Meramec Caverns are a 4.6-mile cavern system in the Ozarks. Once a famous hideout of outlaw Jessie James, the caverns are also the largestcaves in Missouri - a state filled with some 6,000 caves! It's kitsch factor is what draws visitors to it. Thus, the caves were also used as shelter by Native American settlers. The Meramec Caves also feature seven different levels of amazing underground caves to explore and are rated one of the best systems anywhere in the USA! The nifty light shows are to watch out for!

Meramec Caverns timings - Open throughout the year

13. Penn's Cave


The most laidback cave of all, this one is for those who are not keen on hiking or hardcore adventure! The Penn’s Cave is the only one completely navigable by motorboat. A 45-minute boat ride will glide you across some of the most impressive stalactite and stalagmite formations in the Northeast. While on this boat ride, you will hear interesting legends about how locals, threw a French explorer in here to die after he fell in love with the chief's daughter, Nita-Nee!

They also have a large gift shop for gems, rock specimens, plush apparel, books, and a Cave Café.

Penn’s Cave timings - Open throughout the year, except Thanksgiving & Christmas Days & January

14. Moaning Cavern

PC:flickr.com/Don Richards

The Moaning Cavern is one of the best caverns on east coast! The 45-minute guided walking tour will let you explore the cavern at your own space and by this we mean exploring the sights of 100 skeletal remains of those believed to have fallen into the cave and found dating as far back as 13,000 years! The cavern gets its name from the sound made from water dripping into holes on the cavern floor. You can even rappel up and down the 165 feet of the cavern. Come December and the cave has some great events like the annual Caroling in the Cave concert series where a local jazz choir performs a cappella holiday classics in the cave's main chamber and one where you will find Santa rappelling into the cave!

Moaning Cavern timings - Open throughout the year

15. The Lost Sea

Last but not the least, something different than the above, the Lost Sea is located in Sweetwater, Tennessee at the foothills of the Great Smoky Mountains. It is the largest underground lake in the United States, apart from being a part of the larger Craighead Caverns cave system. A guided tour of the cave will offer you a three-quarter-mile walk through the caverns, followed by a glass-bottom boat trip across the 4-acre underground lake, to absorb all the beauty! As you visit this place, don’t miss picking up some great Cherokee artifacts.

The Lost Sea timings - Open throughout the year

Nature certainly has its way with these caves!

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