Beneath the sandstone-capped ridges in central Kentucky lies the most extensive cave system on Earth. With 563 km/ 350 miles of surveyed passageways Mammoth Cave is at least three times longer than any other known cave.

There are two worlds to explore in Mammoth Cave National Park: the extraordinary world of the underground and rugged, forested hill country on the surface. This is one ecosystem linked by water. The Green River is central to Mammoth Cave system.