Mammoth Onyx Cave

One of the most beautiful and easily accessible caves in the US, Mammoth Onyx Cave was discovered in 1799 and opened to public tours in 1922. Tours are scheduled throughout the day and no prior reservations are necessary. The tour is approximately 45 minutes. This is an active cave; when it rains, the water drips down through the ground and into the cave continually creating new formations! There are many different formations to behold in the cave, such as stalagmites and stalactites, cave popcorn and cave cauliflower. Unsure what cave popcorn or cave cauliflower are? Your interpreter will be happy to explain.

Mammoth Onyx Cave is located at Kentucky Down Under Adventure Zoo. Admission to Mammoth Onyx Cave is included in your Kentucky Down Under Adventure Zoo ticket price.


Mammoth Onyx Cave

3700 L&N Turnpike
I-65, Exit 58
Horse Cave KY 42749
Mammoth Onyx Cave Website

Seasons Hours

Open Year Round

Nov. 3, 2013 – March 7, 2015: 9AM to 4PM
March 8 – May 21, 2015: 9AM to 5PM
May 22 – Sept. 8, 2015: 9AM to 6PM
Sept. 9 – Nov. 2, 2015: 9AM to 5PM

© Horse Cave/Hart County Tourist Commission 2023 | All Rights Reserved.