Mammoth Cave: Explore the World’s Longest Cave



Kentucky’s Mammoth Cave National Park may not be on your radar, but it certainly should be. This spectacular place celebrates more than 75 years as a national park on July 1. Its record-breaking caves, diverse forest and fascinating history make it a special experience. 

Learn more about Mammoth Cave’s one-of-a-kind adventure: 

1. Mammoth Cave National Park preserves the world's longest known cave system. Mammoth Cave is a limestone labyrinth with more than 400 miles of it explored, and the park estimates a potential for another 600 miles in its system. In addition, over 200 caves in the park exist as disconnected fragments of the larger Mammoth Cave system.

Several tourists walk through the main room of Mammoth Cave
Visitors stroll through Broadway, or Main Cave, inside Mammoth Cave massive tunnels. Photo by National Park Service.

2. Cave tours are the best way to explore Mammoth Cave National Park. Over 2 million people a year visit the park and more than 500,000 of them take a cave tour. Some tours lead visitors through massive chambers past amazing rock formations. For the more adventurous, wild cave tours challenge visitors with scrambles along drop offs and crawls through tight spaces. Other tours reveal the cultural history of the caves, sharing the stories of early cave explorers as you walk with only lantern light to guide you. No matter what cave tour you take, make sure to follow the park’s clothing guidelines to prevent white-nose syndrome and protect the cave’s bats.

Visitors crawl narrow caverns with head lamps during a Wild Cave Tour.
Current visitors explore the caves during a Wild Cave tour, which includes crawling around inside the cave. Photo by National Park Service.

3. Strong local support helped establish Mammoth Cave as a national park. Secretary of the Interior Hubert Work created the Southern Appalachian National Park Commission in 1925 to survey proposed park sites, including Mammoth Cave. Stephen Mather, first Director of the National Park Service also expressed his support. After years of work acquiring the land for the park and building roads, trails and bathrooms, Mammoth Cave National Park was established on July 1, 1941.

A visitor gazes at the Frozen Niagara that is illuminated by lights.
Frozen Niagara, a flowstone or travertine formation inside the cave. Photo by National Park Service.

4. African Americans were some of the first cave guides. Stephen Bishop, a slave, worked in the cave from 1838 to 1856. Venturing beyond established tour routes, Bishop crossed a frightening landmark known as the Bottomless Pit to discover unmapped areas of the cave system. Unrecognized at the time, pioneers like Bishop helped spark the golden age of cave exploration and established themselves as legends of Mammoth Cave.

Two visitors stare are the towering Ruins of Karnak via a vista point.
Current visitors walk along the trails once pioneered by African American guides. Photo by National Park Service.

5.  Find the unexpected in Mammoth Cave. More than 130 wildlife species inhabit the Mammoth Cave system. The cave boasts some of the richest cavernicolous creatures including 14 species of troglobites (animals that need to live in cave) and troglophiles (animals that can live in or outside cave) known only to exist there. One of the park’s most well known, and unusual, species is the Eyeless Cave Fish, which has adapted to the lightless environment by no longer growing eyes.

A translucent crayfish crawls along the cave floor
One of the interesting creatures found in Mammoth Cave is the cave crayfish pictured here. The cave crayfish are found in the underground streams of Mammoth Cave. Photo by National Park Service.

6. Mammoth Cave National Park includes much more than just a cave. The surrounding forest contains one of the most diverse habitat in the nation, supporting more than 1,300 flowering species and bird species like bald eagles, wood warblers and thrushes. You can see flowers along the hiking trails -- 60 miles of which are open for horseback riding. The park also includes over 30 miles of the Green and Nolin Rivers, with great fishing spots, and scenic kayak and canoe trails.  

Fog rises near Turnhole Bend at Green River during the sunrise.
Green River at Turnhole Bend during the autumn is a beautiful sight. Photo by National Park Service.

7. Mammoth Cave National Park is a World Heritage Site. Recognized for its extraordinary size and scientific importance, Mammoth Cave is one of only 13 natural U.S. sites honored with the title.

Water flows off the edge of a natural opening to Mammoth Cave.
A small waterfall occurs at the edge of a cave entrance. Photo by Eric Blankenship (

8. Karst topography created the park’s huge caves. Mammoth Cave was created by the natural process of limestone erosion, known as karst topography. During this process rain and rivers slowly dissolve and shape soft limestone, creating a vast system of caves. Underground rivers are still carving new passages today. Beyond their scientific and recreational value, karst aquifers like Mammoth Cave provide drinking water for approximately 40 percent of the U.S. population.

Stalactites and stalagmites made of limestone hang from the ceiling in Mammoth Cave.
Mammoth Cave’s travertine stalactites and stalagmites can be seen on tours of Mammoth Caves. Travertine is made of limestone that crystallized out of dripping water. Photo by National Park Service.

9. In the 1800s railroads were the best way to access the cave. The first railroad to the area opened in 1859, and by 1886, the line ran directly to the cave, bringing in tens of thousands of visitors every year. Two of the original locomotives, No. 4 and No. 2, are on display today in the Mammoth Cave terminus at the end of the line. You can use the historic Mammoth Cave Railroad Bike and Hike Trail to access the locomotives via the old railroad corridor.

A stream runs through snow covered hills outside of Mammoth Cave.
Cedar Sink stream in Mammoth Cave National Park in February shows this park’s winter beauty. Photo by National Park Service.

10. The caves are a time capsule that preserve over 5,000 years of human history. Since the 1800s, Mammoth Cave has been a hotbed of scientific discovery, but the history of the caves goes back even further. The first American Indian explorers entered the cave around 5,000 years ago, and for nearly two centuries Native Americans explored and mined the upper three levels of Mammoth Cave. The cave’s atmosphere and natural protection from disturbance have left the over 1,000 archeological sites in good shape, allowing scientists to track the cave’s uses.

Five visitors gaze at the walls of Mammoth Cave as lights illuminate them.
Park goers enjoy closeup views of cave structures and formations during a tour. Photo by National Park Service.

 Don’t miss your chance to experience this one-of-a-kind park. Start planning your trip today.