12 USA Caves So Surreal, You’ll Want to See Their Secret Passages for Yourself

Ready for an adventure that takes you deep beneath the surface? The USA has some of the most decorated caves you’ll ever encounter. These subterranean wonders aren’t just dark, damp holes, but places of wonder with hidden chambers, underground rivers, and geode-filled caverns.

I’ve road-tripped through almost 40 states and seen everything from lava tubes in Hawaii to eerie underground passages to the staggering stalactite sizes in Carlsbad Caverns. So, grab your flashlights, as these 12 caves stand out as some of the best caves in the USA that you absolutely need to see!

1. Ruby Falls

• Location: Chattanooga, Tennessee
• Highlights: Underground waterfall, unique cave formations

Located more than 1,120 feet below Lookout Mountain in Chattanooga, Tennessee, Ruby Falls is a unique cave system with 145 feet underground waterfall that cascades over a series of rocks into a pool below.

Leo Lambert discovered the falls in 1928, and they were named after Lambert’s wife, Ruby. Today, they remain one of the tallest and deepest underground waterfalls open to the public in the United States.

Besides the falls, you’ll see a myriad of formations like stalactites and stalagmites that have been growing for thousands of years.

2. Carlsbad Caverns National Park

• Location: Carlsbad, New Mexico
• Highlights: Massive underground chambers

In the Chihuahuan Desert of southern New Mexico, Carlsbad Caverns is an underground wonder with over 119 caves formed by sulfuric acid dissolution. The main chamber, known as the Big Room, is the largest accessible cave chamber in North America and can fit over six football fields!

As a designated national park, it is incredibly accessible: You can either hike to the entrance or take an elevator directly into the main chamber. There, you are treated to a stupendous display of stalactites, stalagmites, and other unique limestone formations.

One of the most popular characteristics is the Bat Flight Program, where from late spring through early fall, thousands of Brazilian free-tailed bats emerge from the caverns at dusk for their nightly feeding.

3. Lost Sea Cave

• Location: Sweetwater, Tennessee
• Highlights: America’s largest underground lake, glass-bottom boat rides

Hidden beneath the mountains of Sweetwater, Tennessee, is Lost Sea Cave, the largest underground lake in the United States. Discovered by a group of explorers in 1905, this cavern has a vast clear blue lake that you can glide across on a glass-bottom boat ride.

The tour includes stories about the cave’s history and information about its rare animal inhabitants, such as blind cavefish and albino crayfish.

4. Ash Cave

• Location: Hocking Hills State Park, Logan, Ohio
• Highlights: One of the largest recess cave openings, Seasonal Waterfall

In the heart of Ohio’s Hocking Hills State Park, Ash Cave is a magnificent recess cave that is one of the largest cave openings east of the Mississippi River. The path to Ash Cave is an easy, accessible trail through lush forests that leads you to this rock shelter.

As you stand beneath its sandstone cliffs, watch as the serene waterfall gracefully cascades down during rainy months. Once serving as a Native American meeting place, it also acted as a religious gathering site.

5. Wind Cave National Park

• Location: Hot Springs, South Dakota
• Highlights: Unique boxwork formations, extensive passageways

Located in the Black Hills of South Dakota, Wind Cave is renowned for its intricate maze of passageways and unique boxwork formations. These are created by calcite crystals filling in the spaces between thin layers of limestone.

This cave is also one of the most explored in the world, with over 150 miles of mapped and surveyed passageways. In 1903, it was the first cave in the world to be designated a national park.

Two brothers, Tom and Jesse Bingham, discovered the natural entrance to Wind Cave in 1881. Its name comes from the strong winds that can be felt at its entrance due to air pressure differences between the inside and outside.

6. Mammoth Cave National Park

• Location: Mammoth Cave, Kentucky
• Highlights: World’s longest cave system, diverse ecosystems

The cave’s name, “Mammoth,” doesn’t come from woolly mammoth fossils but rather from its ginormous size. Mammoth Cave, in Kentucky, boasts the title of the world’s longest cave system, with over 400 miles of explored passageways, and it’s still growing!

This natural wonder is an absolute labyrinth of limestone tunnels and chambers. Inside, you’ll discover famous segments like the Frozen Niagara, a flowstone formation that resembles a frozen waterfall, and the Rotunda, a massive room known for its impressive dome-shaped ceiling.

7. Lehman Caves, Great Basin National Park

• Location: Baker, Nevada
• Highlights: Ornate formations

Located in Great Basin National Park, Lehman Caves is one of the few limestone caves in a national park. Although the cave system itself consists of just a single cavern stretching about a mile long, you’ll be enchanted by the brilliant “cave shields”—rare, disk-shaped speleothems that look like delicate crystal shields mounted on the cave walls.

The most impressive element of this cave is the “Parachute Shield” formation, which hangs from the ceiling and looks like an upside-down parachute. Other notable formations include draperies that resemble flowing curtains and delicate soda straws that look like thin tubes.

8. Meramec Caverns

• Location: Stanton, Missouri
• Highlights: Colorful formations, historic outlaw hideout

Tucked away in Stanton, Missouri, I visited the subterranean Meramec Caverns when I lived in St. Louis. These colorful caverns are famed for their eye-popping geological formations, including the dazzling “Stage Curtain,” a rare and massive flowstone drapery that wonderfully mimics an elegant theater curtain.

More than just looks, this cavern is steeped in Wild West lore. Legend has it that the infamous outlaw Jesse James and his gang used the labyrinthine tunnels as a hideout to evade lawmen.

Today, visitors can explore these caves through guided tours and see evidence of their visits etched into the cave walls.

9. Timpanogos Cave

• Location: American Fork, Utah
• Highlights: Helictites, three connected caverns

Timpanogos Cave is a network of three limestone caverns connected by passageways in American Fork, Utah. The cave’s most unique feature is its “helictites,” rare formations that defy gravity and grow in any direction rather than straight down or up.

Guided tours through these caves allow visitors to see the delicate helictites up close and anthodites, a delicate needle-like formation.

The trail to reach the entrance of Timpanogos Cave is a steep 1.5-mile hike.

10. Oregon Caves National Monument

• Location: Cave Junction, Oregon
• Highlights: Marble caves, diverse geologic features

In the Siskiyou Mountains of southern Oregon, the Oregon Caves National Monument is a unique system of marble caves formed by acidic water dissolving the surrounding limestone. One of the coolest things about the Oregon Caves is that they are relatively young in geological terms, being around just a few million years old.

The caves are known for their intricate formations, such as “cave bacon,” layered calcite deposits that resemble thin slices of meat hanging from cave walls. Visitors can also spot rare “moonmilk,” a creamy white substance of microscopic crystals and bacteria.

But the highlight of the Oregon Caves is the Hall of Marble, a place with shining, glossy marble walls that look like they’ve been polished to perfection.

11. Sea Lion Caves

• Location: Florence, Oregon
• Highlights: Largest sea cave in the USA, home to sea lions

The Sea Lion Caves in Florence, Oregon, stands as the largest sea cave in the United States. It’s also a bustling habitat for a large population of Steller sea lions and California sea lions who come to rest, breed, and socialize.

This cave results from nearly 25 million years of waves crashing against the coastal cliffs and gradually hollowing out the cave. Visitors can take an elevator down through 200 feet of solid rock, emerge into a large room filled with natural light, and hear the loud, echoing barks of the local inhabitants.

12. Lava Beds National Monument

• Town: Tulelake, California
• Highlights: Over 800 caves formed by flowing lava

Although Hawaii may have the most well-known lava flows in the US and Ape Cave in Washington has the longest lava tube, Lava Beds National Monument has over 800 caves formed by flowing lava.

These caves vary in size and complexity, from the easy-to-navigate Mushpot Cave to the more challenging labyrinths of the Labyrinth and Catacombs Caves. You can take a guided tour or rent equipment and explore on your own.

MY FAVORITE TRAVEL RESOURCES

✈️ Find amazing guided tours and experiences with Viator to maximize your time! 🏘️ Plan ahead and secure your accommodation with Booking.com in advance. 🧾 Rent a car with Discovercars in advance and get the best prices for your day trip adventures.