The following is a list of the longest caves in the United States per length (over 50 kilometres or 30 miles) of documented passageways. Many passageways are still being discovered; this list is based on the latest verifiable data. [1] Some caves and cave systems are partially accessible to the general public. Other caves have restricted access; restrictions may include limiting access to experienced spelunkers or scientific research teams.
Caves or caverns are natural voids under the Earth's surface. Caves often form by the weathering of rock and often extend deep underground. Exogene caves are smaller openings that extend a relatively short distance underground. Caves which extend further underground than the opening is wide are called endogene caves.
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 52,830 acres (21,380 ha) 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.
Wind Cave National Park is a national park of the United States located 10 miles (16 km) north of the town of Hot Springs in western South Dakota. Established on January 3, 1903 by President Theodore Roosevelt, it was the sixth national park in the U.S. and the first cave to be designated a national park anywhere in the world. The cave is notable for its calcite formations known as boxwork, as well as its frostwork. Approximately 95 percent of the world's discovered boxwork formations are found in Wind Cave.
Jewel Cave National Monument contains Jewel Cave, currently the fifth longest cave in the world and second longest cave in the United States, with 220.01 miles (354.07 km) of mapped passageways as of May 2024. It is located approximately 13 miles (21 km) west of the town of Custer in Black Hills of South Dakota. It became a national monument in 1908.
At 150.4 miles (242.0 km), Lechuguilla Cave is the eighth-longest explored cave in the world and the second deepest in the continental United States. It is most famous for its unusual geology, rare formations, and pristine condition.
The Cave Research Foundation (CRF) is an American private, non-profit group dedicated to the exploration, research, and conservation of caves. The group arose in the early 1950s from the exploration efforts at Floyd Collins Crystal Cave, now within Mammoth Cave National Park. Its stated goals were: to promote exploration and documentation of caves and karst areas, initiate and support cave and karst research, aid in cave conservation and protection, and to assist with the interpretation of caves and karst to the public.
Dos Ojos is part of a flooded cave system located north of Tulum, on the Caribbean coast of the Yucatán Peninsula, in the state of Quintana Roo, Mexico. The exploration of Dos Ojos began in 1987 and still continues. The surveyed extent of the cave system is 82 kilometers (51 mi) and there are 28 known sinkhole entrances, which are locally called cenotes. In January 2018, a connection was found between Sistema Dos Ojos and Sistema Sac Actun. The smaller Dos Ojos became a part of Sac Actun, making the Sistema Sac Actun the longest known underwater cave system in the world.
Carlsbad Caverns National Park is a national park of the United States in the Guadalupe Mountains of southeastern New Mexico. The primary attraction of the park is the show cave Carlsbad Cavern. Visitors to the cave can hike in on their own via the natural entrance or take an elevator from the visitor center.
Organ Cave is a large and historic cave in Greenbrier County, West Virginia, USA. The surrounding community takes its name from the cave.
A solutional cave, solution cave, or karst cave is a cave usually formed in a soluble rock like limestone (Calcium carbonate CaCO3). It is the most frequently occurring type of cave. It can also form in other rocks, including chalk, dolomite, marble, salt beds, and gypsum.
The Fisher Ridge Cave System is a cave system located in Hart County, Kentucky, United States, near Mammoth Cave National Park. As of November 2019 it had been mapped to a length of 130.001 miles (209.216 km), making it the fifth-longest cave in the United States and the tenth-longest in the world.
Patricia Kambesis is an American caver, cartographer and educator.
Cave diving is underwater diving in water-filled caves. The equipment used varies depending on the circumstances, and ranges from breath hold to surface supplied, but almost all cave diving is done using scuba equipment, often in specialised configurations with redundancies such as sidemount or backmounted twinset. Recreational cave diving is generally considered to be a type of technical diving due to the lack of a free surface during large parts of the dive, and often involves planned decompression stops. A distinction is made by recreational diver training agencies between cave diving and cavern diving, where cavern diving is deemed to be diving in those parts of a cave where the exit to open water can be seen by natural light. An arbitrary distance limit to the open water surface may also be specified. Despite the risks, water-filled caves attract scuba divers, cavers, and speleologists due to their often unexplored nature, and present divers with a technical diving challenge.
A breathing cave or barometric cave is a rare type of cave in which atmospheric pressure gradients between the inside and outside of a cave cause air to flow in to or out of the cave. The concept of air flowing through a cave is common, however in most caves this airflow is caused by a difference in temperature rather than air pressure; in barometric caves the thermal mechanism inside the cave is not great enough to cause such airflow. The speed of the airflow in barometric caves is directly correlated with the atmospheric pressure difference between the inside and outside of the cave. When the air pressure outside of the cave is higher than that inside the cave air blows into the cave and vice versa; if the air pressures are at equilibrium there is no airflow.
Fitton Cave, also known as Beauty Cave, is located near the Buffalo National River in Arkansas.It contains 17.5 miles of mapped passage as of 2024, and is the longest known cave in Arkansas, and the 188th longest in the world. The cliffs on the Buffalo River harbor 340 known caves, many of which are home to endangered bats. Fitton Cave is gated and access is closely monitored by the National Park Service, due to the spread of White-nose syndrome, a fungal disease that affects bats.