​Photo by Bonne Terre Mine

Exploring Bonne Terre’s Incredible Underground Mine!

Bonne Terre, MO

Located about 50 miles southwest of St. Louis, Missouri, the Bonne Terre Mine holds the world’s largest subterranean lake. To see the wonders of the submerged national historic site and the illuminated Billion Gallon Lake, you’ll have to head to the city of Bonne Terre.

Mammoth architecture, oar carts, scaffolding, grating, staircases, pillars, slurry pipes, and the famed elevator shaft, are just a few of the structures found beneath the surface of the Billion Gallon Lake that you can see with its 100 feet of clear visibility. The lake is illuminated by 500,000 watts of lighting, allowing for both underground boat and walking tours, as well as hosting the world’s largest freshwater dive resort.

Exploring Bonne Terre’s Incredible Underground Mine

Photo by Bonne Terre Mine 

Well, maybe not the center of the Earth, but if you’re a certified diver you can dive The Billion Gallon Lake into the depths of the mine and discover an underground world seemingly frozen in time. Featuring 50 different dive trails and exploratory diving for the more advanced, it is not surprising that National Geographic Adventure named the diving at the Bonne Terre Mine one of the top 10 adventures in America. 

If you decide to dive at Bonne Terre, you’ll see underwater pillars, shafts, archways, walls, and ceilings that seem to reach for miles in a sprawling maze under the town above. Remnants of the past life of the mine are featured on every trail such as shovels, drills, ladders, and ore carts. Another attraction is the electric-blue water resulting from the 500,000 watts of high-powered stadium lighting that illuminates your path. 

Photo by Bonne Terre Mine

If you’re not keen on diving, you can still experience the beauty and awe of the mine on the underground boat and walking tour. The guided boat tour including stops where you can walk around and explore. The tour offers spectacular views of the largest parts of the mine, featuring the first and second levels.

You can walk to the same spots where miners dug with picks and shovels in the 1800s on the Old Mule Trail. Along this tour, you will get to see many of the main attractions, including huge pillar rooms, grand canyons, the Billion Gallon Lake, Trout Pond, underground flower gardens, calcite falls, and ancient abandoned mining tools and rail systems.


If you plan on staying in Bonne Terre for a night or two, the Bonne Terre Mine offers great options for visiting divers and tourists. Located in the rolling foothills of the Ozark Mountains is the nearby Bonne Terre Depot Bed & Breakfast. Constructed in 1909, the national historic depot was a hallmark of the MR & BT railroad and now serves as a completely restored bed and breakfast. This accommodation features guest rooms and detached train car suites, as well as the nostalgic Whistle Stop Saloon. 

Two other accommodations are the Diver’s Lodge, located at the actual Bonne Terre Mine, as well as the Mansion Hill Guest House if you’re after a more casual stay. If you plan on diving, many of the lodge options can be included in dive packages, so be sure to check out the website when booking your stay. 

The Space Museum Is Less Than A Mile Away

Another great attraction that you don’t want to miss in Bonne Terre is the nearby Space Museum. Located within a mile from the Bonne Terre Mine, it only makes sense to check out the world class collections of space artifacts that the museum has to offer while you’re in the area. 

Starting out as a personal hobby of collecting space age artifacts, founder Earl Mullins shared his collection with the public in 2002, hoping to inspire wonder and passion for space exploration in younger generations. Today, Mullin’s collection and the edition of many other exhibits were combined to create The Space Museum, where you can visit, view artifacts from space suits to space rocks, and learn about space exploration and history. 


Content Writer and Social Media Coordinator. I paint, listen to music, and play with my dogs a lot. When I’m not doing all that, I love to read and try new things.

Maeve Miller

Writer, River Travel Magazine