Laurel Caverns is the largest cave in the Commonwealth of Pennsylvania by volume and area. Located in the community of Farmington, it sits on the Chestnut Ridge near Uniontown, roughly 50 miles (80 km) southeast of Pittsburgh.

Initially an unregulated wild cave that was known by locals and word of mouth as "Dulany's Cave" (alternate spelling: "Dulaney's Cave") during the early 1900s, it was owned, during the 1930s, by Norman Cale and his brother, and then later by Cale and his wife, Helen, who opened it to the general public as a show cave on July 1, 1964, and marketed it as "the caverns in the clouds".

Named after Thomas Dulany, the early nineteenth-century owner of the land where the cave was located and first achieved local prominence, Dulany Cave (alternate spelling: "Dulaney's Cave") was reportedly first explored on September 11, 1816, by a party of six men. Headed by John A. Paxton of Philadelphia, that party "tried all passages, even those so small that they had to wriggle or crawl to get through". Describing the last section reached by the team, Paxton described it as the cave's largest, adding:

"This we found to be very spacious, being from 20 to 30 feet wide, from 30 to 80 feet from the floor to the roof, and 1,200 feet in length, with a stream sufficient to turn a grist-mill running its full length. We measured with a line the extreme distance we had been in, and found it to be 3,600 feet, but we must have traveled altogether upwards of two miles."

Still known by locals as "Dulany's Cave" in 1915, it remained an unregulated wild cave well into the 1950s. Even so, by the 1930s, it was a popular attraction for church groups and visiting guests of area residents, who arranged for tours headed by Don Helmick and other knowledgeable guides.

Owned by Uniontown brothers Norman and Roy Cale, beginning sometime around the 1930s, the land near the cavern became the subject of historical research regarding the eighteenth-century operation of Fort Contrechoeur, a stockade that had been erected by the French between 1747 and 1748 during the French and Indian Wars.

By the 1940s, Halloween-themed events were being held inside the cave, billed as opportunities to "explore the dark caverns with the live bats that fly from one end of the cave to the other". During the mid-1950s, the Cales began exploring ways to convert the wild cave into a for-profit tourist attraction.

Still owned by Norman Cale during the 1960s, but now in collaboration with his wife, Helen, the cave was officially opened it to the general public as a show cave on July 1, 1964, with the Cales marketing it as "the caverns in the clouds".

It was then purchased from the Cales later that same year by Emmett J. Boyle Jr. and Ned J. Nakles, two lawyers from Greensburg and Latrobe, who made several safety and entertainment value-related improvements, including the installation of roughly twenty-five miles of electrical cable that supported a new theatrical lighting system.

This cavern features an array of speleological and pseudokarsts formations. Its average temperature is 52 °F (11 °C).

Split into two sections, the entrance into the upper cavern is a network of interconnecting grid-like passages, while its unlit lower cavern, known as its branch-work, consists of subterranean watercourses that flow into a dendritic system of passages.

The steep slope of some passageways on this tour causes an optical illusion known as a gravity hill, similar to the illusion of a ball rolling uphill.

Operators offer a three-hour tour, which includes gravity hill, as well as the cavern's lower branchwork, which is unlit. Because the terrain remains unaltered here, cavern rules require visitors to use helmets and lighting when climbing or crawling over breakdown piles or other obstructions to reach the caverns' chambers and chasmal courses.

The cavern grounds also offer visitors access to a gift shop, mini-golf course, the opportunity to pan for gemstones, and fossil-study activities, and also serve as a wildlife viewing locale during operations to tourists. As a popular destination for school field trips, the cavern's owners have adopted a no firearms policy.

• Official Laurel Caverns website
• Show Caves of the United States: Laurel Caverns

39°47′59″N 79°42′42″W / 39.79961°N 79.71161°W / 39.79961; -79.71161