How Many Caves Are There in the World?

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Beware: You should never explore wild caves alone or without proper gear. Consider getting in touch with a Grotto of the National Speleological Society at or a qualified cave club. These groups are skilled and will train you. Without sufficient knowledge, preparation, and equipment, cave exploring can lead to serious injury or death.

There are thousands of caves in the world. In the United States alone, experts have discovered more than 45,000 caves, and thousands more caves remain hidden and unidentified. What’s perhaps more incredible is that more than 10,000 caves are in the state of Tennessee!

This is because caves form naturally, often well beneath the surface of the earth, so we can never really know until we’ve found them.

Some caves are large and reach depths of over 2000 meters, while others are very small and it is difficult for explorers to penetrate into them. Therefore, no one can give you a concrete answer.

The structure of most caves is also quite complex. It is not like what you see in the movies or documentaries. They are like sinkholes, shafts, or have interconnecting galleries that even baffle cavers and compel them to classify them in different sub-areas.

We have countless underwater caves as well. Water moves through them consistently. Some of them are partially occupied by air and they are flooded at times as well.

If you want to have a solid idea regarding how many caves are in the world and their formation, consider checking out the ‘Geology of Caves’ by W.E. Davies and I. M. Morgan. This book tells you about how caves occur in a wide variety of rocks, as well as how they range in sizes from a small room to miles-long interconnecting passages.

After reading this book and doing some extra research, you will have a pretty good idea of how many caves are scattered throughout the world. You might figure out an accurate estimate, but unfortunately, we will probably never truly know.

Geology of Caves: Usgs General Interest Publication      Paperback – January 30, 2013

Geology of Caves: Usgs General Interest Publication Paperback

The scientific study of caves is called speleology (from the Greek words spelaion for cave and logos for study). It is a composite science based on geology, hydrology, biology, and archaeology, and thus holds special interest for earth scientists of the U.S. Geological Survey.

Types of Caves

Understanding the types of caves is another aspect that can assist you in perceiving how many caves a specific country has. For example, if a country has too many volcanic mountains, there is a good chance it has many lava caves also.

Here are some popular and most common types of caves in the world.

Some cavers stand and admire a massive tunnel in a lava cave.
Lava caves naturally form where there is volcanic activity, as the outer cooler lava hardens and forms tunnels like this one.

Solution Caves

These caves form by the dissolving of rock. These rocks are often soluble limestone rocks like chalk, dolomite, marble, etc. It is a million years long chemical corrosion and physical erosion process. The water continues to flow in the empty or air-filled space of the cave and deposits calcium carbonate in it that extends its boundaries and makes it form an unusual shape.

This is the most frequently occurring type of cave, and no one can give a right estimate about how many solution caves are in the world. 

Since mostly they are formed deep inside the earth in the weak spots and cracks. If you are interested in knowing more about them, study the ‘Mammoth Cave’.

Mammoth Cave is in South Central Kentucky and has more than 345 miles in length. More than 500,000 people visit this cave each year. Visit it to see how water dissolved Mississippian-aged carbonate rocks to form this cave. Scientists call this process ‘Karst Topography’.

A picture showing the many orange/brown colored hanging stalactites in a solution cave.

Lava Caves

You find lava caves in volcanic rocks.

Shaped by the flowing lava from a volcanic eruption, lava caves often provide a once in a lifetime experience to cavers. It is a long volcanic process in which the lava cools down and creates space inside the rock and also develops a continuous hard crust that is quite visible on the walls and surface of the cave.

Surprisingly, it is not only the Earth that has lava caves. Mars has numerous lava tubes as well, as it hosts large volcano systems, perhaps larger than those on Earth.

The Kazumura Cave in Hawaii is one of the most famous lava caves in the world.

To comprehend how many lava caves are in a specific region, you need to have a rough estimate about how many volcanic mountains or rocks it has.

Two explorers venture into Kazumura Cave, a lava cave in Hawaii.
Kazumura Cave in Hawaii.

Glacier Caves

This type of cave forms within the ice of glaciers.

It is carved out by water running through it. Mostly you find these caves under the glacier’s ice. For that reason, it is immensely hard to estimate how many glacier caves are in the world. Besides, glacier caves are dangerous. No one knows what is under the surface of the glacier. Small seasonal water streams erode the bed in the ice and make the entire surface vulnerable.

The water streams inside the glacier cause sinkholes also which become the death bed for many cavers. Though the death rate in the glacier caves isn’t too high as they aren’t visited by casual explorers, they still pose a risk and compel you to take precautionary steps.

There is another reason why it is tough to estimate the number of glacier caves. It doesn’t help that with climate change, these glaciers are changing dramatically, and caves are always shifting with them.

In the glacier caves, the water spins like in a water mill. It tries to move vertically and seeps into the depth of the glacier. That’s why the structure of the glacier caves differs, making it tougher for exploration.

Mendenhall Glacier Cave's newest ice cave poses some risks. This pic shows a few explorers standing in the blue-lit cavern.

Sea Caves

Sea caves form mostly by the action of the waves.

The action of the waves creates a hollow chamber in a coastal cliff. It is a thousand years-long process that relies on both erosion and depositional activities. You find these caves throughout the world; they are common and visited by thousands of visitors each month.

A magnificent sea cave with a natural sunroof in the ceiling.

Surprisingly, most sea caves range from 100-350 feet above sea level. This sheds a mysterious light on their history and the sea levels of ancient times.

Bit don’t confuse sea caves with underwater caves. Sea caves are usually not packed with water, whereas underwater caves are often entirely submerged. These are typically only explored by professional divers and in groups. We recommend learning more about cave diving, but it’s best to get your feet wet with standard caves first.

Cave diving takes place with underwater caves, but it is significantly more dangerous. It’s important to be sure you are aware of the risks and prepare appropriately before you try.


Understanding these types of caves should give you a good idea about the number of caves we have on our planet. In reality, they are countless and it is almost impossible to know even about their rough numbers. Since most of them exist deep inside our earth system. Our satellites and machinery aren’t advanced enough to thoroughly explore them, yet.

However, if you are researching some specific region, it can be easy to count and explore the already discovered caves. You can also read about the geology of the region to guess the number and types of caves it has.

If you’re a heavy reader, here’s another suggestion: Into The Planet by Jill Heinerth. It is an incredible book on caving underwater. Read this to find out how a professional caver faces the terror and beauty of the Earth’s unknowns. 

This book will expand the boundaries of your imagination and help you understand the mystery of caves from a new perspective.

If you’re interested in cave diving and locations to consider, check out the most famous underwater caves here.

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