The longest cave in the world is now even longer!

Posnov / Getty Images

Spelunkers from the Cave Research Foundation recently mapped out 8 additional miles of pathways in Mammoth Caves in Kentucky. Mammoth Caves is the states only national park and is considered the worlds longest cave system.

Jonathan Waldron

On September 12th the National Park announced on its Facebook page, “THE LONGEST CAVE IN THE WORLD IS NOW EVEN LONGER!!!” The recent discovery increased the caves total documented length to an astonishing 420 miles!

Jonathan Waldron

The cave earned its “world’s longest” superlative all the way back in 1969, when just 65 miles of passages were surveyed—many by the CRF. For more than six decades, Mammoth Cave has partnered with the nonprofit to explore its complex system; each year, volunteers descend into the farthest reaches of the cave to survey previously undocumented tunnels. Because lasers can’t bend around obstructions, researchers must manually measure cave passages in a painstaking process.

Michelle Jaqua

Which means every mile of cave length was physically visited and surveyed. Many of the cave trips are long and challenging , involving climbing, vertical exposure, squeezes, crawlways, water, and mud. After the trip, cartographers turn the data collected on the cave trip into a map. Other volunteers provide surface support. It’s a first-rate effort for a world-class cave.

Michelle Jaqua

Though the official Mammoth Cave map has yet to be expanded to include the newly mapped tunnels, you probably won’t be able to explore them any time soon. Visits by the public are restricted to guided tours of several dozen prescribed routes, the longest of which lasts six hours and covers just 5 miles. That means there are hundreds of miles kept off-limits to visitors.

Susan Blackford

Thanks to the ongoing work of the CRF, who have put in thousands of hours of work over the last 60-plus years, there are plenty more tunnels waiting to be uncovered. When it comes to discoveries in Mammoth Cave, there truly is no end in sight!

Mammoth Cave is located in beautiful Kentucky at  1 Visitor Center Parkway in Mammoth Cave, KY 42259.  For more information, click here.