The Coolest Underground Attractions in Every State (Would You Explore #24?)

SAVING & SPENDING - TRAVEL
Discover the subterranean marvels that make each state uniquely cool.
Updated April 11, 2024
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When it comes to truly unforgettable travel experiences, the coolest adventures often lie beneath our feet.

From glittering crystal caves to prehistoric fossil beds, every state in the U.S. has something extraordinary hidden just below the surface.

Get ready to step up your travel game — these underground wonders are guaranteed to leave you awestruck.

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Alabama: Cathedral Caverns State Park (Woodville)

Richard/Adobe cathedral caverns state park

While there’s plenty that people can do underground, it's what nature does that’s fantastic. The towering cathedral-like caves at Cathedral Caverns State Park caves are the perfect example.

Located here is Goliath, one of the largest stalagmites in the world, measuring 45 feet tall.

Alaska: Mendenhall Ice Caves (Juneau)

matthew knutson/Adobe mendenhall glacier ice cave

Though not fully underground, the Mendenhall Ice Caves are within a 12-mile-long glacier, allowing you to walk through the ice to see a unique formation difficult to find anywhere else.

Arizona: Antelope Canyon (Page)

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Antelope Canyon is nothing short of a natural sculpture with bright red and orange natural carvings that brighten in daylight.

The canyon, which is estimated to be at least eight million years old, has two components, the Upper and Lower areas, both of which are stunning slot canyons.

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Arkansas: Glory Hole Falls (Deer)

westtexasfish/Adobe glory hole falls arkansas

What if you could see an underground waterfall? That’s exactly what’s happening at Glory Hole Falls. It’s not an easy climb — it’s slippery and has a 500-foot elevation for over two miles.

Yet, when you get to this enclosed cavern, you’ll quickly notice the hole at the very top and the falling water from it.

California: Old Sacramento Underground (Sacramento)

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The Old Sacramento Underground is an educational, historical exploration of the city's underground area.

You’ll see where and how the streets and buildings were built and how the city had to be raised due to flooding. You may hear some stories about the gamblers and murderers in this area, too.

Colorado: Wetherill Mesa (Mesa Verde)

Stephen/Adobe step house cliff dwellings

Wetherill Mesa is a series of 600 cliff dwellings, some of which are as much as 820 years old. It’s hard not to be captivated by the ancient dwellings hand-built by the Pueblo Indians.

You can tour the area with a park ranger, though self-exploration trails are available. It’s only open from May through October and may close due to tricky conditions.

Connecticut: Squaw Cave (Bolton)

Dudarev Mikhail/Adobe highlighted cave in Vietnam

Squaw Cave is a hidden gem tucked into the cliffside. You’ll need to travel along the Hop River Linear Trail to get there.

Though small, it is one of the few caves in the state and a fantastic way to explore the beauty of the Appalachian Mountains.

Delaware: Indian Cave (Wilmington)

Kennymax/Adobe landscape of cave in Vernazza

Also known as the Beaver Valley Rock Shelter Site, Indian Cave is the only formally recognized cave in the state. It’s small at just 56 feet long, and you’ll have to stoop to get into it.

Yet, it has a beautiful history of providing shelter to Native Americans who traveled through the region.

Florida: Florida Caverns State Park (Tallahassee)

Gerri/Adobe tunnel in the florida caverns

The Florida Caverns State Park features the only air-filled caverns publicly accessible in the state.

Take a guided tour through an extensive cave system, feel the cool temperature drop, and see stalactites, stalagmites, draperies, and flowstones along the way.

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Georgia: Consolidated Gold Mine (Dahlonega)

Mishainik/Adobe gold mine underground tunnel

The Georgia Gold Rush was very much a part of the history of the Consolidated Mine. This 92-acre mine is the oldest in the state.

The first gold was discovered accidentally in this area in 1828, 20 years prior to the California Gold Rush. Tunnel diggers have worked the mine since, and you can now tour it.

Hawaii: Thurston Lava Tube (Hawaii National Park)

marcel/Adobe illuminated thurston lava tube

You know about Hawaii’s volcanos and fascinating beaches, but what about the Thurston Lava Tube?

Traveling through the 500-year-old tube that once carried 2,000-degree lava is risky. You could trip, have to walk through standing water, dodge rock falls, and manage low ceilings.

Idaho: Shoshone Ice Caves (Shoshone)

jon/Adobe Tourist standing in an ice cave

The Shoshone Ice Caves take you about 100 feet under lava, where you can see the natural ice cave that formed over centuries.

You’ll need to walk down about 80 steps, and tours are not always available due to conditions, but it’s certainly worth exploring to see the rock formations, icy conditions, and the colors.

Illinois: Illinois Caverns (Waterloo)

Dean/Adobe stone passage

Since 1901, Illinois Caverns has been a tourist destination showcasing cave formations, including rimstones, flowstones, stalagmites, and soda straws.

About six miles of passages have been mapped, but there could be more to explore.

Indiana: City Market Catacombs (Indianapolis)

David Soanes/Adobe st. callixtus catacombs in rome

You may not have known that under Indianapolis is a series of catacombs, but you can tour them. The Roman-like catacombs are just under the Whistler Plaza in the City Market area.

You won’t see any crypts here, but rather brick-linked paths that will take you to views of Tomlinson Hall and City Market.

Iowa: Maquoketa Caves State Park (Maquoketa)

Nicholas J. Klein/Adobe maquoketa park rocky tunnels

Maquoketa Caves State Park has the most caves of any state park and a 6-mile trail system that takes you on a journey through geological formations.

Check out Dancehall Cave, a 1,100-foot cave you can explore with or without a guide.

Kansas: Strataca (Hutchingson)

Calin Stan/Adobe targu ocna salt mine

Strataca is a salt mine museum built on one of the world's largest deposits of rock salt. The salt here formed more than 275 million years ago and extends as far as 275 feet into the earth.

A two-hour tour will allow you to explore the underground region, including 150 miles of tunnels.

Kentucky: Mammoth Cave (Mammoth Cave)

K.A/Adobe  large walking path inside of Mammoth Cave near Kentucky

Mammoth Cave is the longest-known cave system in the world. Passing through it means exploring deep river valleys.

With over 405 miles of documented passages and 10 miles of tunnels you can explore, it's an exciting and breathtaking experience no matter which adventure you dare to take.

Louisiana: Wolf Rock Cave (Leesville)

Rosey Pinecone/Adobe wolf rock cave native

Wolf Rock Cave was carved out some 24 million years ago. It’s part of the Kisatchie National Forest.

As you navigate this park and the cave, you’ll see bands of sand, sandstones, clays, and numerous rock formations. What do you think they look like?

Maine: Tunnels Under Bangor (Bangor)

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You may have no idea as you walk through various sites in Bangor that there’s a series of tunnels under the city. They’re on private property, so you need permission to visit them.

What’s under there? Various things, including an old coal bunker, bathrooms, and ongoing, expansive tunnels, without a clear indication of their use.

Maryland: Crystal Grottoes (Boonsboro)

Lucas/Adobe waterfall in the cave

Crystal Grottoes is the only underground show cave in the state of Maryland. Though it’s not always open due to weather, it’s a fantastic exploration of what’s under the earth’s surface.

Found in the 1920s after blasting through limestone, the cave has been giving tours since. When it opened, those tours were just seven cents a person.

Massachusetts: Upton Cave (Upton)

oxygen64/Adobe jaskinia raptawicka cave

Upton Cave is the largest cave structure in the state of Massachusetts. Quite stunning in its construction, this man-made cave is one of about 300 structures in the region.

It starts with a tunnel and moves into a beehive-shaped chamber 11 feet high. Some believe European explorers created it, but others believe native people did so long before.

Michigan: Quincy Mine (Hancock)

Rebecca/Adobe old quincy mine building

The Quincy Mine offers tours that take about an hour and are sure to be mesmerizing.

It’s a fascinating introduction to the local geology here, from the rock formations to miners' work centuries before.

Minnesota: Mystery Cave State Park (Preston)

Ivelin/Adobe cristal onyx cave

If you’re thinking about fishing in a stream and hiking for a trip this year, visit Mystery Cave State Park. You’ll find the longest caves in the state, stretching a full 13 miles underground.

It’s a good idea to book one of the underground tours so you can check out the underground pools of water and the cave formations.

Mississippi: Cat’s Den Cave Preserve (Smith County)

sv_production/Adobe entrance to an unknown cave

Cat’s Den Cave Preserve is perfect for outdoor trekking, fishing, and definitely some caving.

You’ll likely stumble on the cave, but if you’re brave enough to trek inside, you’ll find 200 feet of passages with rimstone, flowstone, and beautiful rock formations.

Be sure to check out the three-bird orchids that make this area home, but beware of the snakes, tree frogs, and bats that call this area home.

Missouri: Onondaga Cave State Park (Leasburg)

Green Heron Photo/Adobe onondaga cave formations

Onondaga Cave State Park offers a fantastic view of nature’s beauty underground. You’ll see dripping stalactites, huge stalagmites, and stunning carvings from water passing through.

Tours are booked throughout the open season. It’s worth the tour since it will also give you a history of the area. The cave is on the National Natural Landmark Registry.

Montana: Old Butte Underground City (Butte)

Ron/Adobe ptarmigan tunnel

Montana may be known for its mining and mining tunnels, but the tunnels under Butte are different. There’s everything you can imagine, from a barbershop and stores to a speakeasy.

Though the city was rebuilt after fire and flooding, these tunnels were a part of the gangster activity. Though many tunnels are underwater, others are preserved and can be toured.

Nebraska: Happy Jack Peak and Chalk Mine (Scotia)

Xalanx/Adobe couple of hikers exploring a cave

When you visit Happy Jack Peak and Chalk Mine, you’ll see a unique display of chalk. With over 6,000 feet of honeycombed caverns, you can check out the uniquely soft walls of the tunnels.

This is the only pillar mine and chalk room that’s openly accessible to the public in the country.

Nevada: Fire Cave (Overton)

Klodien/Adobe valley of fire cave

For those planning a visit to Las Vegas, make it a point to stop at the Fire Cave. The Fire Cave is a part of the Valley of Fire.

It’s not a huge cave, but it is worth exploring to see the beauty and delicate balance of the underground natural carving.

New Hampshire: Abandoned Copper Mine (Lyman)

Roberto Sorin/Adobe copper and gold underground tunnel

Located in Paddock Mine in Lyman, you’ll find an old, abandoned copper mine. The walls shine, but don’t expect to go home with pockets full.

The mine spans more than 1,000 acres in full and is one of the largest copper mines in the region. Enter through a hard-to-climb-into tunnel as long as you’re okay with enclosed spaces.

New Jersey: The Sterling Hill Mine (Ogdensburg)

ungvar/Adobe fluorescent rocks of sterling hill

The Sterling Hill Mine is the fourth oldest in the country and was the last working mine underground in the state.

You can take the quarter-mile-long tour to reach the rainbow tunnel, a fascinating fluorescent tunnel that’s a stunning natural formation not found anywhere else in the world.

New Mexico: Carlsbad Caverns National Park (Carlsbad)

nlphoto/Adobe carlsbad caverns national park

Located in the Chihuahuan Desert lies about 119 caves known as the Carlsbad Caverns. As a part of our National Park System, you can explore this area with proper entry.

Throughout that journey, you’ll find numerous caverns tucked into every corner and bend. The Big Room, the largest limestone chamber, is 255 feet high and spans 4,000 feet.

New York: Lockport Caves (Lockport)

pisotckii/Adobe taldinsky tavdinsky cave

If you’re in Niagra Falls, New York, make the trip to Lockport to explore the underground caves. You’ll notice dolomite and limestone bedrock that developed over millions of years.

A simple walking tour lets you get up close to a variety of formations. H haunted cave lantern tours are available that tell the story of those who are said to have lost their life in the area.

North Carolina: Swannanoa Tunnel (Old Fort)

Olena/Adobe tunnel with the light bulbs

The Swannanoa Tunnel is the longest hand-dug tunnel in the state and is more than 1832 feet long. Even more impressive, it was built in 1879, long before most machinery was accessible.

The tunnel passes through the Blue Ridge Mountains. As you walk through, consider that someone’s hard work went into carving out that massive space in mountain rock.

North Dakota: University of North Dakota Tunnels (Grand Forks)

haleturek.raw/Adobe fairview lift bridge tunnel

Under the University of North Dakota are tunnels connecting various buildings. They are still accessible and are a great way to get around the campus during winter.

The problem is they are said to be haunted. Many stories have been told about those who roam the tunnels, so it may be best to just run from one building to the next.

Ohio: Brewery Tunnels (Cincinnati)

apratim/Adobe a row of aged whiskey barrels

About 40 feet under a nail salon in Cincinnati is a massive 10,000-square-foot space. These are lagering tunnels used for decades as a way to create some of the most forbidden beer.

Developed in 1855, the tunnels were pre-prohibition and were used to help with the fermentation process. They were rediscovered in 2018, and these tunnels can now be toured.

Oklahoma: Tulsa’s Network of Underground Tunnels (Tulsa)

altitudevisual/Adobe walking through a tunnel

Under the city streets in Tulsa, there are dozens of underground tunnels. The network of tunnels was first built in the 1900s, though they’ve been expanded over time.

There are many stories and ideas about what the tunnels were used for, including a way to move alcohol during Prohibition. You can tour them to come up with your own ideas.

Oregon: Caves National Monument (Cave Junction)

Shaun Hunter/Wirestock/Adobe oregon caves national monument

One of the fun things about the Oregon Caves National Monument and Preserve is that there are tours you can feel good about bringing your kids on here.

To reach them, you’ll climb to 4,000 feet on the slopes of the Siskiyou Mountains. Tours are available during the safe-to-explore season.

Pennsylvania: Bube’s Brewery and Catacombs (Mount Joy)

Sved Oliver/Adobe tunnels of catacombs underground

Not only can you tour the catacombs here, but you can also enjoy a meal at Bube’s Brewery and Catacombs. You’ll need to descend 43 feet into the catacomb structure to get there.

A lager beer brewery built in the mid-1800s, this fabulous location pays homage to the history of early fermentation.

Rhode Island: Deadman’s Cave (Cranston)

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Deadman’s Cave is quite unique. Approaching it, you’ll notice the coal and graphite ledges and beautiful rock formations.

Once a mine that’s no longer operational, this cave area is still accessible through a tiny passage along the back of the rock formation. Find it and explore the area with care.

South Carolina: Stumphouse Mountain Tunnel (Walhalla)

Kenneth Keifer/Adobe stumphouse mountain tunnel

Located within Stumphouse Park, the Stumphouse Mountain Tunnel was built in the 1850s as part of the Blue Ridge Railroad project but was never completed due in part to the Civil War.

Today, you can explore the tunnel. It’s an easy, short walk into the tunnel (you can bring the kids on this one) and explore the interior structure.

South Dakota: Wind Cave National Park (Custer County)

khezylicious/Adobe wind cave national park

Wind Cave National Park is home to bison and elk, but underground is one of the world's most complex and longest cave systems.

With a guided tour, you can bend, turn, crawl, and climb through the cave system (with a guide to help you) to explore this beautiful location.

Tennessee: Ruby Falls (Chattanooga)

miami2you/Adobe ruby falls waterfall in cave

Ruby Falls is a fantastic underground, cascading waterfall. It plummets some 145 feet down Lookout Mountain. Discovered in 1928, it’s a fantastic experience.

There are actually a series of waterfalls here. You’ll descend about 260 feet down in a glass elevator to see them. As you move down, you’ll see the ancient cave formations and trails.

Texas: Inner Space Cavern (Georgetown)

Kit Leong/Adobe inner space cavern

Another stunning display of nature’s beauty, Inner Space Cavern is an exceptionally preserved deep cave in the heart of Texas.

Formed over time by water passing through the area, it’s estimated to be 20 million years old. The cave is beautiful and maintains a temperature of 72 degrees all of the time.

Utah: Homestead Crater (Midway)

lacey/Adobe homestead crater utah

The Homestead Crater is a 55-foot-tall geothermal spring. It took over 10,000 years to form this beehive-shaped limestone rock formation.

It’s located on the Homestead Resort. That means you’ll need to book a tour to see the Homestead Crater.

Vermont: Arthur Park (Burlington)

rickbowden/Adobe cressbrook cave

Arthur Park has a secret hillside cave carved into the side of the mountain here. With the crystal clear waters and stunning coloring on the walls, this is a fascinating place to go caving.

Often called Devil’s Den by locals, the Intervale Sea Caves, as they are formally known, are vibrant spaces to explore.

Virginia: Luray Caverns (Luray)

vm2002/Adobe wishing well luray caverns

Luray Caverns were first discovered in 1878 and are filled with stunning showmanship of underground features, including flowstones, columns, and stalactites.

There’s a museum where you can purchase self-guided tour tickets and learn about the caverns. You’ll get a walk-through history with underground ceilings reaching 10 stories high.

Washington: Seattle Underground (Seattle)

Alex/Adobe seattle underground tour

Several tour companies do Seattle Underground tours, and most will provide you with fantastic views of a world you may never have thought existed in such a modern city.

When you walk these tours, you get to see the way the streets looked long ago and explore the beauty of history.

West Virginia: Greenbrier Bunker (White Sulphur Springs)

Mulderphoto/Adobe underground soviet military bunker

The Greenbrier Bunker is a super cool historical landmark built in 1962 as a Cold War fallout shelter and a place to relocate Congress should there be a need.

You can explore it in a 90-minute private or group tour into the deep chambers and corridors. No cameras or electronic equipment is allowed — not even your cell phone.

Wisconsin: Crystal Cave (Spring Valley)

Jacob/Adobe crystal cave in spring valley

True cave lovers will enjoy Crystal Cave. There are rock formations around every bend, and the space feels alive with the way the formations seem to be dripping off the ceiling.

In reality, Crystal Cave is about a mile long and could be a great place to do some gem mining. Outside, you can book a tour and learn the area's history.

Wyoming: Bridger Underground Coal Mine (Point of Rocks)

ARAMYAN/Adobe stairs through the pit

Bridger Underground Coal Mine is one of the most important mines in the region, pulling out large coal deposits to heat homes throughout the country.

It’s an impressive sight, as is the sheer scale of the location. Tours are limitedly available but worth trying for.

Bottom line

C Haas/peopleimages.com/Adobe friends hiking

The next time you’re itching for adventure, skip the well-trodden tourist trail and delve into the hidden depths. Your next jaw-dropping discovery might be just beneath your feet.

So, grab your best travel credit card and a sense of wonder, and explore the coolest underground attractions in every state.

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