Mammoth Cave National Park
Mammoth Cave National Park is a national park of the United States in south-central Kentucky. It encompasses portions of Mammoth Cave, the longest known cave system in the world. The park's are located primarily in Edmonson County, with small areas extending eastward into Hart and Barren counties. The Green River runs through the park, with a tributary called the Nolin River feeding into the Green just inside the park.
The cave system has formally been known as the Mammoth–Flint Ridge Cave System since 1972, when a connection was discovered between Mammoth Cave and the even longer system under Flint Ridge to the north. As of 2025, more than of passageways had been surveyed, over 1.5 times longer than the second-longest cave system, Mexico's Sac Actun underwater cave.
The park was established as a national park on July 1, 1941, after oft-contentious eminent domain proceedings whose consequences still affect the region. It was named a World Heritage Site on October 27, 1981; an international Biosphere Reserve on September 26, 1990; and an International Dark Sky Park on October 28, 2021.
Mission
The park's mission is stated in its foundation document:Geology
Mammoth Cave developed in thick Mississippian-aged limestone strata capped by a layer of sandstone, which has made the system remarkably stable. It is known to include more than of passageway. New discoveries and connections add several miles/kilometers to this figure each year.The upper sandstone member is known as the Big Clifty Sandstone. Thin, sparse layers of limestone interspersed within the sandstone give rise to an epikarstic zone, in which tiny conduits are dissolved by the natural acidity of groundwater. The epikarstic zone concentrates local flows of runoff into high-elevation springs which emerge at the edges of ridges. The resurgent water from these springs typically flows briefly on the surface before sinking underground again at the elevation of contact between the sandstone caprock and the underlying massive limestones. It is in these underlying massive limestone layers that the human-explorable caves of the region have naturally developed.
The limestone layers of the stratigraphic column beneath the Big Clifty, in increasing order of depth below the ridgetops, are the Girkin Formation, the Ste. Genevieve Limestone, and the St. Louis Limestone. The large Main Cave passage seen on the Historic Tour is located at the bottom of the Girkin and the top of the Ste. Genevieve Formation.
Each of the primary layers of limestone is divided further into named geological units and sub-units. One area of cave research involves correlating the stratigraphy with the cave survey produced by explorers. This makes it possible to produce approximate three-dimensional maps of the contours of the various layer boundaries without the necessity for test wells and extracting core samples.
The upper sandstone caprock is relatively hard for water to penetrate: the exceptions are where vertical cracks occur. This protective layer means that many of the older, upper passages of the cave system are very dry, with no stalactites, stalagmites, or other formations which require flowing or dripping water to develop.
However, the sandstone caprock layer has been dissolved and eroded at many locations within the park, such as the Frozen Niagara room. The contact between limestone and sandstone can be found by hiking from the valley bottoms to the ridgetops: typically, as one approaches the top of a ridge, one sees the outcrops of exposed rock change in composition from limestone to sandstone at a well-defined elevation.
At one valley bottom in the southern region of the park, a massive sinkhole has developed. Known as Cedar Sink, the sinkhole features a small river entering one side and disappearing back underground at the other side.
Visiting
The National Park Service offers several cave tours to visitors. Some notable features of the cave, such as Grand Avenue, Frozen Niagara, and Fat Man's Misery, can be seen on lighted tours ranging from one to six hours in length. Two tours, lit only by visitor-carried paraffin lamps, are popular alternatives to the electric-lit routes. Several "wild" tours venture away from the developed parts of the cave into muddy crawls and dusty tunnels.The Echo River Tour, one of the cave's most famous attractions, took visitors on a boat ride along an underground river. The tour was discontinued for logistical and environmental reasons in the early 1990s.
Mammoth Cave headquarters and visitor center is located on Mammoth Cave Parkway. The park can be accessed directly from I-65 at Exit 48. The parkway connects with Kentucky Route 70 from the north and Kentucky Route 255 from the south within the park.
History
Prehistory
Human activity in Mammoth Cave traces back five thousand years. Several sets of Native American remains have been recovered from Mammoth Cave, or other nearby caves in the region, in both the 19th and 20th centuries. Most were mummies, representing examples of intentional burial, with ample evidence of pre-Columbian funerary practice.An exception to purposeful burial was discovered when in 1935 the remains of an adult male were found under a large boulder. The boulder had shifted and settled onto the victim, a pre-Columbian miner, who had disturbed the rubble supporting it. The remains of the ancient victim were named "Lost John" and exhibited to the public into the 1970s, when they were interred in a secret location in Mammoth Cave for reasons of preservation as well as emerging political sensitivities with respect to the public display of Native American remains.
Research beginning in the late 1950s led by Patty Jo Watson, of Washington University in St. Louis has done much to illuminate the lives of the late Archaic and early Woodland peoples who explored and exploited caves in the region. Preserved by the constant cave environment, dietary evidence yielded carbon dates enabling Watson and others to determine the age of the specimens. An analysis of their content, also pioneered by Watson, allows determination of the relative content of plant and meat in the diet of either culture over a period spanning several thousand years. This analysis indicates a timed transition from a hunter-gatherer culture to plant domestication and agriculture.
Another technique employed in archaeological research, at Mammoth Cave, was "experimental archaeology" in which modern explorers were sent into the cave using the same technology as that employed by the ancient cultures whose leftover implements lie discarded in many parts of the cave. The goal was to gain insight into the problems faced by the ancient people who explored the cave, by placing the researchers in a similar physical situation.
Ancient human remains and artifacts within the caves are protected by various federal and state laws. One of the most basic facts to be determined about a newly discovered artifact is its precise location and situation. Even slightly moving a prehistoric artifact contaminates it from a research perspective. Explorers are properly trained not to disturb archaeological evidence, and some areas of the cave remain out-of-bounds for even seasoned explorers, unless the subject of the trip is archaeological research on that area.
Besides the remains that have been discovered in the portion of the cave accessible through the historic entrance of Mammoth Cave, the remains of cane torches used by Native Americans as well as other artifacts such as drawings, gourd fragments, and woven grass moccasin slippers are found in the Salts Cave section of the system in Flint Ridge.
Earliest written history
The tract known as the "Pollard Survey" was sold by indenture on September 10, 1791 in Philadelphia by William Pollard. of the "Pollard Survey" between the North bank of Bacon Creek and the Green River were purchased by Thomas Lang Jr., a British-American merchant from Yorkshire, England, on June 3, 1796, for £4,116/13s/0d. The land was lost to a local county tax claim during the War of 1812.Legend has it that the first European to visit Mammoth Cave was either John Houchin or his brother Francis Houchin, in 1797. While hunting, Houchin pursued a wounded bear to the cave's large entrance opening near the Green River. Some Houchin Family tales have John Decatur "Johnny Dick" Houchin as the discoverer of the cave, but this is highly unlikely because Johnny Dick was only 10 years old in 1797 and was unlikely to be out hunting bears at such an age. His father John is the more likely candidate from that branch of the family tree, but the most probable candidate for discoverer of Mammoth Cave is Francis "Frank" Houchin, whose land was much closer to the cave entrance than his brother John's. There is also the argument that their brother Charles Houchin, who was known as a great hunter and trapper, was the man who shot that bear and chased it into the cave. The shadow over Charles's claim is the fact that he was residing in Illinois until 1801. Contrary to this story is Brucker and Watson's The Longest Cave, which asserts that the cave was "certainly known before that time." Caves in the area were known before the discovery of the entrance to Mammoth Cave. Even Francis Houchin had a cave entrance on his land very near the bend in the Green River known as the Turnhole, which is less than a mile from the main entrance of Mammoth Cave.
The land containing this historic entrance was first surveyed and registered in 1798 under the name of Valentine Simon. Simon began exploiting Mammoth Cave for its saltpeter reserves.
19th century
In partnership with Valentine Simon, various other individuals would own the land through the War of 1812, when Mammoth Cave's saltpeter reserves became significant due to the Jefferson Embargo Act of 1807 which prohibited all foreign trade. The blockade starved the American military of saltpeter and therefore gunpowder. As a result, the domestic price of saltpeter rose and production based on nitrates extracted from caves such as Mammoth Cave became more lucrative.In July 1812, the cave was purchased from Simon and other owners by Charles Wilkins and an investor from Philadelphia named Hyman Gratz. Soon the cave was being mined for calcium nitrate on an industrial scale, utilizing a labor force of 70 slaves to build and operate the soil leaching apparatus, as well as to haul the raw soil from deep in the cave to the central processing site.
A half-interest in the cave changed hands for $10,000. After the war when prices fell, the workings were abandoned and it became a minor tourist attraction centering on a Native American mummy discovered nearby.
When Wilkins died his estate's executors sold his interest in the cave to Gratz. In the spring of 1838, the cave was sold by the Gratz brothers to Franklin Gorin, who intended to operate Mammoth Cave purely as a tourist attraction, the bottom long having since fallen out of the saltpeter market. Gorin was a slave owner, and used his slaves as tour guides. Stephen Bishop was one of these slaves and would make a number of important contributions to human knowledge of the cave, becoming one of Mammoth Cave's most celebrated historical figures.
Stephen Bishop was an African-American slave and a guide to the cave during the 1840s and 1850s, was one of the first people to make extensive maps of the cave, and named many of the cave's features.
Stephen Bishop was introduced to Mammoth Cave in 1838 by Franklin Gorin. Gorin wrote, after Bishop's death: "I placed a guide in the cave – the celebrated and great Stephen, and he aided in making the discoveries. He was the first person who ever crossed the Bottomless Pit, and he, myself and another person whose name I have forgotten were the only persons ever at the bottom of Gorin's Dome to my knowledge."
"After Stephen crossed the Bottomless Pit, we discovered all that part of the cave now known beyond that point. Previous to those discoveries, all interest centered in what is known as the 'Old Cave'... but now many of the points are but little known, although as Stephen was wont to say, they were 'grand, gloomy and peculiar'."
In 1839, John Croghan of Louisville bought the Mammoth Cave Estate, including Bishop and its other slaves from their previous owner, Franklin Gorin. Croghan briefly ran an ill-fated tuberculosis hospital in the cave in 1842–43, the vapors of which he believed would cure his patients. A widespread epidemic of the period, tuberculosis would ultimately claim the life of Dr. Croghan in 1849.
In 1866, the first photos from within the Mammoth Cave were taken by Charles Waldack, a photographer from Cincinnati, Ohio, using a very dangerous method of flash photography called magnesium flash photography.
Throughout the 19th century, the fame of Mammoth Cave would grow so that the cave became an international sensation. At the same time, the cave attracted the attention of 19th century writers such as Robert Montgomery Bird, the Rev. Robert Davidson, the Rev. Horace Martin, Alexander Clark Bullitt, Nathaniel Parker Willis, Bayard Taylor, William Stump Forwood, the naturalist John Muir, the Rev. Horace Carter Hovey, and others. As a result of the growing renown of Mammoth Cave, the cave boasted famous visitors such as actor Edwin Booth, singer Jenny Lind, and violinist Ole Bull who together gave a concert in one of the caves. Two chambers in the caves have since been known as "Booth's Amphitheatre" and "Ole Bull's Concert Hall".