A grand passage inside Mammoth Cave
America's Best Idea ★ National Parks Series

Mammoth
Cave

The World's Longest Cave
More than 426 miles of surveyed passages under the Kentucky hills — plus a full national park of river, forest, and dark sky on the surface. Explored free, budget, mid-range, or premium. A research-based guide.
🕳
426+ mi
World's Longest Cave
And still growing
🎟
FREE
Park Entry
Cave tours ticketed
🌡
54°F
Cave Temp
Year-round — bring a layer
🌌
Dark Sky
Certified Park
Since 2021
SDF·BNA
Airports
Louisville / Nashville
Why Mammoth Cave

A Whole Park, Above and Below

The Green River in Mammoth Cave National Park

The longest cave on Earth — and more.

Mammoth Cave holds the longest known cave system in the world: over 426 miles surveyed, and still growing. Ranger-led tours walk you through cathedral-scale passages and delicate formations that people have explored for two centuries.

But most visitors miss half the park. On the surface there's a quiet Green River, more than 80 miles of forest trails, and some of the darkest night skies in the eastern United States — all free, and all reason to stay more than an hour.

🕳 The Cave
Ranger tours from a short walk to a 6-hour wild crawl.
🚣 The Green River
The river that carved it — canoe, kayak, and the ferry.
🌳 Surface Trails
80+ miles of forest, sinkholes, and backcountry.
✨ Dark Sky
A certified International Dark Sky Park since 2021.
Four Ways to Experience Mammoth Cave

Plan It Your Way

5 Can't-Miss Experiences

The Places That Define Mammoth Cave

Pairs Naturally With

A Kentucky–Tennessee Road Trip

Mammoth Cave is about 90 minutes from Nashville and a few hours from Chattanooga and the Great Smoky Mountains. Chain them for a cave-and-mountains road trip through the mid-South.

Plan Your Trip

Turn Inspiration Into a Plan

Free Ultimate Adventure Planner

Budget calculators, packing checklists, and a heads-up when each new guide drops — all free. Grab it and plan your trip the easy way.

Get the Free Planner →