Mystic Caverns and Crystal Dome

Mystic Caverns and Crystal Dome are former show caves located between the cities of Jasper and Harrison, in the state of Arkansas, U.S., on the Arkansas Highway 7 Scenic Byway near the defunct amusement park Dogpatch USA. Sometimes called "the twin caves" because they are within 400 feet (120 m) of each other, the two caves maintain a year-round temperature of 58 °F, contain more formations per foot than any other caves in Arkansas, and are open for public tours year-round except during the January flooding season. A third cave on the site, Not Much Sink cavern, has been deemed too dangerous to allow public tours. Mystic Caverns, which has operated commercially since the late 1920s, is older than any other commercially operated cave in Arkansas, with the exception of Onyx Cave in Eureka Springs, and perhaps nearby Diamond Cave in Jasper, which has been toured since 1925. Crystal Dome was discovered in the mid-1960s during landscaping operations at Dogpatch USA. Great care was taken to preserve this pristine cave, and as a result 90% of it is still being formed. Tours began in the Crystal Dome in 1981. Since 2021, the two caves have been closed indefinitely.

Cave data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).