This Tennessee Town Is Home to America's Largest Underground Lake — and You Can Sail a Glass-bottomed Boat on It

Welcome to Sweetwater, Tennessee's underground lake.

The underground lake from The Lost Sea Adventure
Photo: Trey Sullins/Courtesy of The Lost Sea Adventure

So, you've traveled the globe and reached corners far and wide. You've seen and done it all — or, so you think. But there are still places even the most well-trodden travelers have yet to discover. You just have to go under the Earth's surface to get to them.

Those looking for a unique getaway that will certainly add to their already stellar travel repertoire can head to the town of Sweetwater, Tennessee. There, travelers will find America's largest underground lake, known as The Lost Sea.

The Lost Sea is located inside the greater Craighead Caverns, an extensive cave network that extends from Sweetwater to Madisonville, Tennessee. The sea is calm, still, and clear, and you can tour it on a glass-bottomed boat to see what lurks beneath the surface.

As explains, the cave has likely been used by animals for thousands of years. As for humans, it notes that the "caverns have been known and used since the days of the Cherokee Indians. From the tiny natural opening on the side of the mountain, the cave expands into a series of huge rooms. Nearly a mile from the entrance, in a room now known as 'The Council Room,' a wide range of Indian artifacts including pottery, arrowheads, weapons, and jewelry have been found, testifying to the use of the cave by the Cherokees."

Though the lake has been widely visited since the early 1900s, Lake Scientist reports, there has been very little research or scientific exploration into the waters. Though one diver noted on the website, "We had no way of knowing what depths we would encounter, but we all suspected that the depths would be in excess of 100 feet very shortly after beginning the exploration. We were correct. The underwater section of the cave angled down just as sharply as the dry cave did."

Though you cannot readily go diving in the cave, you can very easily hop aboard one of those aforementioned glass-bottomed boats for a 75-minute tour, which begins with a .75-mile walk to the lake, then a ride around nearly four acres of water. On the tour, guides will even point out a few gorgeous formations known as anthodites, or cave flowers. Admission to the cave starts at $13.95. Learn more about the caves and book your visit here.

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