
Located about one hour south of St. Louis lies the World's Largest Subterranean Lake under the city of Bonne Terre, Missouri.
Named “One of America’s Top 10 Greatest Adventures” by National Geographic, Bonne Terre is not only a remarkable destination but also a marvel of engineering. This unique attraction, located in Eastern Missouri, boasts the distinction of being one of the world’s largest man-made caverns, a testament to both human ingenuity and the geological wonders of the state. The cavern was created as a lead mine in the 19th century, and over the years, it has transformed into an underground landscape that attracts adventurers, divers, and nature lovers.

Within the expansive network of underground tunnels and chambers, Bonne Terre features the world's largest subterranean lake, a body of water that stretches over 100 acres and reaches depths of more than 200 feet in some areas. The crystal-clear waters of this lake provide a unique ecosystem. Visitors may explore the lake through guided scuba diving tours, or walking tours and boat rides.
In addition to its geological significance, Bonne Terre is steeped in history and folklore. On tours, visitors learn about the mining process, the geology of the area, and conservation as the attraction works to preserve this unique ecosystem. This is a true bucket list experience as Bonne Terre is one of Missouri's most unique hidden gems.
A Hidden Gem in Missouri:

Originally founded in 1860, Bonne Terre Mine was a deep-earth lead mine that played a significant role in Missouri's mining industry, becoming one of the world's largest producers of lead ore during its operational years. The mine operated continuously for over a century, extracting millions of tons of lead ore, used for ammunition, batteries, and radiation shielding. As the demand for lead fluctuated and mining practices evolved, the mine ultimately ceased operating in 1962. Today, visitors take guided tours of the historic site.
Boat Tour of Bonne Terre Mine, Missouri:

On the one-hour tour of Bonne Terre Mine, visitors enter the mine (and exit) via a 65-step staircase. The tour guides visitors through the mine's five levels, following the ancient mule paths where miners labored more than 150 years ago. We discovered that mules, known for their stubborn nature, were perfect for the job not just because of their strength, but also because they understood their boundaries. Unlike horses, who are loyal and will keep working to satisfy their owner, mules will pause for food and rest, which is more beneficial for their health.

The highlight of the tour is the expansive seventeen-mile-long Billion Gallon Lake. This is an engineering marvel and a natural wonder, illuminated by an impressive 500,000 watts of stadium lighting.
Guides share the rich history and geological significance of the area. Among the notable sites are the iconic No. 1 Elevator, which once served as a crucial access point for miners., old ore carts, that transported lead ore, and weathered catwalks. The tour emphasizes both the geological and economic history of the mine for the community.
FAQ for Visiting Bonne Terre Mine:
The guided one-hour tour of Bonne Terre Mine (185 Park Ave, Bonne Terre, Missouri) requires walking, including a 65-step staircase in and out. It is not accessible for wheelchairs.
Service animals and pets are not permitted.
The mine is 65 degrees, year-round, so dress accordingly.
No food or drink is allowed on the tour.
Home to the largest freshwater scuba diving venue in the world. (Reservations required.)
Pin for Later:

Additional Missouri Vacation Inspiration:
First-Timer’s Guide to Gateway Arch National Park: St. Louis, Missouri
8 Best Places to Camp in Missouri: Top Campgrounds for Nature Lovers
Underground Boat Tour of the World's Largest Subterranean Lake in Missouri
Romantic Getaway to Missouri’s Wine Country: The Best Destinations for Couples
3 Christmas-Inspired Missouri Vacation Rentals for Any Time of Year
This looks like such a fun adventure--adding it to our list next time we make it to Missouri.
That seems like a nice experience! I wish there were more photos!
Wow! I never knew such boat tours existed! This looks so much fun and adventurous.
If i had not seen this post, I would have never known that this existed. Thank you for sharing.
What is this place?! haha I am from Missouri (St. Louis) and have not heard of it before. Guess I need to go back for a visit, it's less than an hour from where I grew up!