The park's 52,830 acres (about 21,390 hectares) is located in Edmonson County, Kentucky, with small areas extending eastward into Hart County and Barren County. It is centered around the Green River, with a tributary, the Nolin River, feeding into the Green just inside the park. Almost two million people visit the park every year.
Mammoth Cave is a system in thick limestone strata capped by a layer of sandstone, making the system remarkably stable. It comprises over 336 miles of passageway. The cave was a significant source for saltpeter production for the manufacture of gunpowder at one time, especially in the War of 1812.
Mammoth Cave was mapped and named extensively by Steven Bishop, a slave guide to the cave during the 1840s and 1850s.