Kartchner Caverns State Park is a state park of Arizona, United States, featuring a show cave with 2.4 miles (3.9 km) of passages. The park is located 9 miles (14 km) south of the town of Benson and west of the north-flowing San Pedro River. Long hidden from view, the caverns were discovered in 1974 by local cavers, assisted by a state biologist who helped in its preservation.
The park encompasses most of a down-dropped block of Palaeozoic rocks on the east flank of the Whetstone Mountains.
The caverns are carved out of limestone and filled with spectacular speleothems which have been growing for 50,000 years or longer, and are still growing. Careful and technical cave state park development and maintenance are designed to preserve the natural cave system.