The Best Caves to Visit in National Parks | World's Largest Cave, Glacier Caves, & Underwater Lakes

Throughout the country, there are approximately 17,000 caves. Some are much larger than others, some have features that puzzle scientists, and some are still being discovered to this day.

Nearly every state is home to at least one cave. Delaware, however, has long been known as the "caveless state". If you count a 56 ft long hole in a rock that is too small to be in after only a few paces as a cave, then technically Delaware has one cave.

Rhode Island is another state that the number of caves they have is debatable. The few caves they have are rather small and many are along the coast formed by water, if not under water.

On the other side of the spectrum, Tennessee is home to the most caves is the country. Despite its size, there are around 10,000 caves within the state!

Within the National Parks, there are several caves worth visiting. In fact, some of the National Parks are named after the cave they are home to.

Before we get to the list of caves you should visit, here are some different cave formations I think you should know. This way, you have a few things to look for when you go exploring the caves.

Stalactites

According to the Oxford Languages Dictionary, a Stalactite is "a tapering structure hanging like an icicle from the roof of a cave, formed of calcium salts deposited by dripping water".

These range in size from a couple inches to nearly 100 feet tall. Once they meet they ground or another formation, they are no longer considered stalactites since they are no longer free-hanging.

Stalagmites

Also defined by Oxford Languages, a stalagmite is "a mound or tapering column rising from the floor of a cave, formed of calcium salts deposited by dripping water".

This is basically a reverse stalactite.

I remember the difference between these two by thinking that stalacTITES hold tight to the ceiling.

Columns/Pillars

These form when a stalactite meets up with a stalagmite and fuse together. Guinness World Records has given the title of world's tallest column to a column in Thailand the measures nearly 202 feet tall! (see picture below)

Cave Bacon

This is just a silly one, but you'll probably hear it a lot. This is a type of formation you'll see in caves that really looks like bacon. The other name for cave bacon is flowstone. This name makes sense since this formation is formed by water flowing over a ledge leaving behind this mineral deposit. You'll usually see cave bacon around walls and ledges in the cave for this reason.

Cave Fried Eggs

This is another silly one for you. Fried eggs are a formation that look fun, but have a bit of a rough story. These form when stalagmites are knocked over (typically by people) and they begin the process of forming again. The "yolk" in the center of the fried egg is the build up of minerals rebuilding the stalagmite.

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Here are six National Parks that have caves worth a visit. You'll notice that the first three National Parks I mention are named after their impressive cave.

Mammoth Cave National Park

Located in Kentucky, this is the world's longest cave, earning itself the rightful name of Mammoth Cave. In total, there are 420 miles of surveyed passageways and who knows how many more miles could be down there. The world's second longest cave (Mexico's Sistema Sac Actun underwater cave) is only half that length with 234 miles.

In addition to being incredibly long, this cave is full of large rooms including a dome with a height of 192 feet. You certainly won't feel claustrophobic in this cave!

On the tour, you will encounter stairs and some occasional low ceilings.

Carlsbad Caverns National Park

This National Park has a total of 119 limestone caves, many of which are worth the view.

Carlsbad Caverns (the cave that the park is named after) is a labyrinth of underground chambers. Though there are more than 30 miles of passageway, only 3 of those miles are open to visitors.

Being 1,600 feet underground, this is the second deepest limestone cave in the US (the first being the recently discovered Tears of the Turtle cave in Montana at 1,659 feet).

Wind Cave National Park

Located 500 feet under the surface of South Dakota, there are 150 miles of surveyed cave passageway and a collection of lakes.

Wind cave is most known for its boxwork (seen below), which is a rare cave formation. This formation resembles a honeycomb grid on the surfaces throughout the cave.

This feature was formed by calcium carbonate crystalizing in the cracks between rocks that have since then eroded. All that is left behind is the boxwork grid.

Hawaii Volcanoes National Park

The Thurston Lava Tube in Hawaii is 600 feet long, and in some places the ceiling is over 20 feet high.

This cave is estimated to have been formed roughly 500 years ago when a volcano erupted. Compared to most caves, this is a relatively new cave. The cave was discovered in 1913 by a local newspaper publisher named Lorrin Thurston, hence the name of the cave.

This cave is easily accessible making it great for all groups including families with kids.

Great Basin National Park

This National Park is home to many beautiful sites and activities. Lehman Cave is just one of them.

This two mile cave is the longest cave in the state of Nevada and is considered to be the most decorated cave in the state. This means it has a lot of features around such as stalagmites, stalactites, columns, flowstones (cave bacon), and shields.

Shields (as seen in the picture below) are a fairly rare formation but many are found in Lehman cave. This is perhaps what Lehman cave is most known for.

There are a few different tour options available to best fit your needs. If you are visiting with kids, then consider taking a shorter tour. If you are interested in the full experience then feel free to take a longer tour. Both tour options include 70 stairs, so this is not the most handicap accessible cave.

Wrangel-St. Elias National Park

Here in Alaska, you can imagine that many of the caves you might find are in the glaciers themselves. These caves are for experienced hikers who are up for a challenge.

Glacier caves are otherworldly and beautiful, but can also be quite dangerous. It is easy to get lost in the caves or fall into a deep crevice. Keep in mind, that the National Parks in Alaska are much less developed than those of the mainland. You won't find trails and signs throughout the park to keep you in the best looking and safest spots. For those reasons, I would recommend going with a glacial cave tour group rather than exploring on your own. Luckily for you, there are many great companies who offer these services.