Ozark Underground Lab (aka OUL) Has the Largest Cave System in the US

Ozark Underground Lab (OUL) is located in Taney County, Missouri off a long dirt road. If you go to their website you will get the impression that this is just a company that does water testing and the like. Don't let that fool you in the slightest... OUL is the best-kept secret in the world!

Located on some the most heavily karsted terrain anywhere, this is, as far as I know, the largest cave system in the US. But lets talk about the above ground stuff first. OUL is used my many colleges for field trips. I initially discovered this gem with a biology class on caving. We rented some vans and went up for the weekend and ooooh how amazing this trip was! Yes, I've been back since then... but I'm going to write on my first experience.

When we arrived we were greeted by the owner, Tom Aley... Ozark Underground Lab is solely owned and operated by him and his wife. This is not a public tourist trap, and all the better for that. He gave us a tour of the land above the main part of the cave so he could explain in depth just what the term karst terrain meant.

Once thought to exist only sporadically, we now recognize that 40% of the US land mass east of Tulsa, Oklahoma is underlain by karstic aquifers. OUL is the most unique natural karst laboratory in the world, consisting of more than 800 acres of land underlain by 2 miles of accessible caves with who knows how many more miles of the system that they haven't yet explored. I know of at least another 2 miles they are exploring but will not let anyone else into yet.

Oh yeah, I was gonna explain just what Karst Terrain is, huh? Well, it is "Terrain with special landforms and drainage characteristics due to greater solubility of certain rocks in natural waters than is common. Name derived from a province in Slovenia, where this type of landform was first described." (from the Glossary of Speleological and Caving Terms, Australian Speleological Federation Inc.) In other words, groundwater flows much differently in karst areas, and faster. Pollutants can spread easier, and the offshoot of this faster flowing water is sink holes and cave systems.