Mammoth Cave National Park

caves · Kentucky · geology · underground rivers

World's Longest Cave. Mammoth Cave holds the record as the longest known cave system in the entire world. It's so huge that the next longest cave isn't even close to its size.

Underground Rivers Flow. The Green River runs through the park above ground, but there are also rivers flowing underground inside the cave system. These hidden rivers carved out the massive tunnels over millions of years.

Huge Protected Area. The park covers 52,007 acres of land spread across three Kentucky counties: Edmonson, Hart, and Barren. That's enough space to protect this incredible natural wonder for everyone to explore.

Nolin River Meets Green River. A tributary called the Nolin River flows into the Green River right inside the park boundaries. These waterways shaped the landscape and continue to be part of what makes the cave system so special.