Mammoth Cave National Park

Mammoth Cave National Park in central Kentucky is home to, by far, the longest cave system in the world. There are 405 miles of discovered cave tunnels within Mammoth Cave National Park, a distance that is two times as long as the second-longest cave system in Sac Actun, Mexico.

A cave of this caliber takes millions of years to develop, and the geology of the Kentucky region contains the perfect conditions for such a cave to form. Kentucky is known as a karst landscape, an area of land where water moves rapidly underground and dissolves rock. As rainwater and snow fall to the ground, they bond to carbon dioxide, which makes the water slightly acidic. The acidic water works its way through the soil and and begins to slowly dissolve the limestone rock that is so common in the Kentucky region, forming sinkholes (which are found by the hundreds in this region) and caves.

Soluble limestone rock is common in cave systems throughout the world. An insoluble sandstone roof makes Mammoth Cave unique and special. The insoluble sandstone protects the limestone below it, keeping the cave very dry from the rainwater seeping through the soil. The dry environment of the cave explains why there are no calcite flowstone formations. On the other hand, the dryness of the cave does allow for delicate gypsum formations, which are extremely rare and beautiful. In addition, beautiful stalagmites and stalactites grow where the sandstone roof has eroded and allowed water to interact with the limestone.

Over thousands of years, the dissolved rock begins to open up small crawl-ways. Over millions of years of limestone erosion, huge passageways and rotundas begin to appear. On ranger-led tours of the caves you will have the opportunity to see both of these amazing geological phenomena.

Cave Tours

Certain cave tours are only available during specific seasons of the year. Be sure to check with the National Park System online or by calling the visitor center in order to see which cave tours are available. Reservations are not required for these tours, but they are strongly recommended because they can fill up very quickly. All requests for reservations must be made two weeks in advance of your anticipated tour date.

Strollers, tripods, flash photography, and all child backpack carriers are not allowed on the cave tours unless noted otherwise.

• Frozen Niagara: This tour lasts about one hour and covers a quarter-mile. It is easy and great for visitors with small children or elderly family members.
• Domes and Dripstones: This tour lasts about two hours and covers three-quarters of a mile. It is moderate, mainly because visitors on the tour must walk a total of approximately 500 stairs. Gypsum formations, stalactites, and stalagmites are all visible on this tour.
• Great Onyx Lantern Tour: This tour lasts about 2.5 hours and covers 1 mile. It is moderate, and all formations are viewed with the natural light of lanterns (other tours typically have artificial lighting throughout).
• Cleaveland Avenue: This tour lasts about 2.5 hours and covers 2 miles. It is moderate. This tour has the most abundant showings of gypsum formations, which come in various different formations.
• Grand Avenue: This tour lasts about four hours and covers 4 miles. It is strenuous because visitors encounter a little over 700 stairs on this journey. The entirety of Cleveland Avenue is included on this trip.
• Wild Cave: This tour lasts about six hours and covers 5 miles. It is extremely strenuous. Visitors must be aged 16 and over in order to go on this tour. This tour requires squeezing through narrow spaces, crawling in even narrower spaces, and is easily the most intense tour that is offered by the park. Proper footwear is required, and if chest and hip measurements are greater than 42 inches, visitors will not be allowed on the tour because they will be physically unable to fit through the narrow spaces that this exploration requires.
• Violet City Lantern Tour: This tour lasts three hours and covers 3 miles. It is strenuous and lit only by natural lantern lighting.
• Gothic Avenue: This tour lasts two hours and covers 1 mile. It is moderate. This tour enters through the old historic entrance and explores one of the most historically significant sections of the cave.  
• Star Chamber: This tour lasts 2.5 hours and covers 2 miles. It is moderate and conducted with lantern light. It is a very historical tour that discusses the experience of early tour guides and visitors.
• Discovery Tour: This tour is a half-hour and covers three-quarters of a mile. It is easy and visits one of the largest rotundas in the cave.

Surface Activities

There are many ranger-led activities that do not go inside the caves. Birdwatching, wildflower education, coffee with a ranger, heritage walks, and ranger-led hikes are just some of the many opportunities for ranger-led experiences in the park. The rangers are full of helpful information that extends far beyond their beautiful cave system.

In addition, there are about 84 miles of trails in the park. These trails are mostly used for horseback riding and hiking, but there are also designated trails for mountain biking. The Green River, located in the park, is a popular place to go kayaking, canoeing, boating, and fishing.

The Buffalo Creek + Sal Hollow Loop is a particularly popular trail that is filled with waterfalls, massive sinkholes, creek crossings, and wildflowers.

Camping

The park offers many camping opportunities. There are three developed campgrounds and over a dozen primitive backcountry campsites that are located either in the woods or by the Green River. Backcountry camping requires a permit, which can be obtained for free in the backcountry permit office in the park's visitor center.

• Mammoth Cave Campground: This campground is located a quarter-mile from the visitor center. The campground's 105 camping sites are open seasonally and require a reservation.
• Maple Springs Group Campground: This campground is 6 miles from the visitor center and 3 miles from the Green River. These sites are specially designed for larger groups of campers and horsepackers. There are eight total sites on this campground.
• Houchin Ferry Campground: This site contains 12 primitive camping spots and is located right by the Green River. Spots are open year round. Reservations are not accepted.