If you’re interested in exploring caverns and underground caves in Tennessee, a visit to the Lost Sea Adventure in Sweetwater TN is an absolute must.
Located in the foothills of the Great Smoky Mountains an hour north of Chattanooga TN and Lookout Mountain, the Lost Sea refers to the tourist attraction and underground lake, while the cave system is called Craighead Caverns.
The Lost Sea caverns are home to the largest of all non-subglacial underground lakes in the USA, and the second largest in the entire world.
It’s the only underground lake in Tennessee, with an underground boat tour that allows you to explore a huge section of the Sweetwater TN cave that you can’t see on foot.
Read on for our in-depth guide to Craighead Caverns and the Lost Sea in Sweetwater TN, including info on tours, exploring the adventure caves, the lake cave boat tour, and more.
Craighead Caverns/Lost Sea Adventure Info
ADDRESS: 140 Lost Sea Rd, Sweetwater TN, 37874
LOST SEA ADVENTURE HOURS: Open 9AM-6PM daily
LOST SEA DAILY TOUR PRICES: Adults ages 13+ $24.95, Kids ages 4 to 12 $14.95, Children ages 3 and under FREE
WILD CAVE TOUR PRICES: Daytime Wild Tour $37; Overnight Wild Tours $44-$47 per person, depending on group size.
DRIVING DIRECTIONS FROM CHATTANOOGA TN
From Chattanooga, take I-24E for about 5 miles to exit 185B, to I-75N towards Knoxville. Continue on I-75 N for 58.4 miles, then take exit 60 for TN-68 towards Sweetwater/Spring City.
Turn right onto TN-68 S/New Hwy 68 and follow it for 7.3 miles. Take a left onto Lost Sea Rd, and the Craighead Caverns entrance will be in o.2 miles on the right.
DRIVING DIRECTIONS FROM KNOXVILLE TN
From Knoxville, take I-40W via the ramp to Nashville and follow it for 20.2 miles. When it forks, keep left to continue on I-75S, following the signs for Chattanooga.
Follow I-75S for 24.1 miles, then take exit 60 for TN-68 toward Sweetwater/Spring City. In 0.4 miles, turn left onto TN-68 S/New Hwy 68 and follow it for 7.5 miles.
Take a left onto Lost Sea Rd, and the Craighead Caverns entrance will be in o.2 miles on the right.
The History of Craighead Caverns
Although the concept for the Lost Sea in Tennessee didn’t begin to take shape until 1915, Craighead Caverns have been used by humans for centuries.
They were named for original owner Chief Craighead, who used the East Tennessee caverns as a meeting place for Cherokee tribal councils. An array of Indian artifacts (including pottery, weapons, and jewelry) have been found nearly a mile from the Lost Sea entrance in a cave now known as “The Council Room.”
After European settlers made their way to the Blue Ridge Mountains of Tennessee in the 1820s, they began used the Lost Sea caverns (which maintain a constant 58°F temperature) for storing potatoes and vegetables.
During the Civil War, the Confederate Army mined the Sweetwater TN cave for saltpeter, an essential ingredient used to make gunpowder. Graffiti in the cave from 1863 has been carbon tested and authenticated as being 160 years old!
The underground cavern lake was discovered in 1905 by a 13-year-old local, Ben Sands. He played in the caves often, and crawled into a room so large he couldn’t see its walls with his lantern. He threw mud balls in all directions and heard splashes.
Unfortunately, by the time he convinced his dad to investigate, the water level of the lake in the cave had risen, so he could no longer find the entrance.
But when local explorers re-discovered the cave decades later, Sands got the credit. A beaming portrait of him visiting the attraction as an elderly man adorns the wall of The Lost Sea caverns entrance today.
In 1939, explorers found the fossilized remains of a Pleistocene Jaguar and an Elk fawn, which led to an excavation by paleontologists from the American Museum of Natural History in New York City.
Exploring Craighead Caverns
Craighead Caverns is a little more off-the-beaten-path than major Tennessee caves such as Ruby Falls. Located between the small towns of Madisonville and Sweetwater TN, it’s surrounded by pastoral farms.
Where the Ruby Falls cave is narrow and filled with intricate geological formations, Craighead Caverns is more expansive. And where tours at Ruby Falls run like clockwork, in our experience the Lost Sea caverns tour felt more casual and leisurely.
Our Lost Sea guide chatted with guests amiably before briefly outlining the rules (which also appear on signs at the entrance), instructing us not to touch anything due to the vulnerability of the geological formations in the caves.
Then he led us across a narrow wooden bridge to see one of the cave’s few examples of stalactite (which hang down from the ceiling) and stalagmite (which grow up from the floor) formations.
Our young guide had an expansive knowledge of the Lost Sea caverns features, pointing out anthodites, a.k.a. “cave flowers.” These cave formations have long, feathery white crystals that look like tiny versions of Superman’s “Fortress of Solitude.”
Making our way down deeper into the caverns, we saw the late-1800s graffiti, an authentic Appalachian moonshine still that was found there, a wooden vat used to cook saltpeter, and even some small waterfalls.
There are lots of interesting little details along the way, but the entire walk to the Lost Sea’s main attraction– the world-famous underground lake of Sweetwater TN– takes no more than 20 to 25 minutes.
The Underground Lake at the Lost Sea Adventure
The Lost Sea measures approximately 800 feet long and 220 feet deep, with a maximum depth of around 70 feet. This makes it second to Namibia’s Dragon Breath Cave among the largest non-subglacial underground lakes in the world.
We’ve written about how much we love lakes many times, and have visited countless lakes on 6 continents. But the Lost Sea’s underground lake was like nothing we’d ever seen, with colored lighting casting an eerie, mysterious glow.
This is one of the few caves with boat rides in the entire world, and the voices of everyone on our Lost Sea tour became hushed and reverent as soon as we laid eyes upon the gorgeous lake.
I couldn’t tell you how long our Lost Sea boat ride lasted, because we were so thoroughly mesmerized by what proved to be an almost otherworldly experience.
Warm lights with autumn colors illuminated the water just enough to draw our attention to the trout that live there. Our guide explained that the fish were brought in as a tourist attraction years ago, and are fed by the staff regularly.
Our eyes eventually began to adjust to the dim lighting of the Lost Sea caverns, but it was still a strain to see the far reaches of it.
There’s no music, so the only sound in the cave is that of an aerator used to help the fish get more oxygen. The overall effect is truly magical, and precisely what you’d want from an underground cave in Tennessee.
Due to the incline, the hike back up to the top of the cave was a challenge for some guests on our Lost Sea Adventure tour.
But thankfully the guides took it slow and easy, stopping for rest (and questions) several times along the way as we walked back to the Craighead Caverns entrance.
READ MORE: The 10 Best Lakes in Tennessee to Visit
Other Lost Sea Adventure Tours
Once you exit through the gift shop (which offers a quirky collection of souvenirs and other tchotchkes), you’ll have a chance to explore a charming village that includes a general store, old-time blacksmith’s workshop, sweet shop, and more.
But if you want to spend even more time exploring Craigshead Caverns, check out the Lost Sea’s Wild Cave Tours, which is designed for groups such as Boy Scouts, Girl Scouts, schools, camps, and churches.
In addition to the regular cavern tour, daytime and overnight Wild Cave Tours take visitors into undeveloped cave rooms that require some crawling through cracks and crevices to reach hidden nooks.
During these tours, guides take more time to point out striking geological formations such as anthodites (of which the Lost Sea contains 50% of the world’s known formations).
Note that adult chaperones are required for the overnight caving excursions, which have a required minimum of 12 participants. Long pants are also required, as are good flashlights with extra batteries, sleeping bags, and ample drinking water.
It’s a rare opportunity for camping inside this unique Tennessee cave system, and all participants can purchase a “Lost Sea Wild Cave Spelunker” as a keepsake of their incredible experience. –by Bret Love; all photos by Bret Love & Mary Gabbett