The Lost Sea: America’s Largest Underground Lake

5 October 2022

What a thrill to sail the Lost Sea! The Lost Sea is a Registered Natural Landmark, where you will tour mysterious caverns with guides who will make it educational and fun. Wide sloping walkways take you on an adventure to some largest rooms of any cavern in the Southeast, where the temperature remains a pleasant 58 degrees year round. The tour takes approximately one hour. All you will need is a sweater and some comfortable walking shoes.

TownMagic-The-Lost-Sea Wild Cave Tour

The deep is the Lost Sea? Everyone loves to ask this question and more as they tour the mysterious underground lake and the beautiful regions of the cavern.

Can You Swim in The Lost Sea?

No, but your Lost Sea Adventure tour includes a glass-bottom boat ride that glides across America’s Largest Underground Lake. The cave and the lake are lit with subdued colorful lights, making it an unforgettable experience. During your boat ride, the guide will throw out handfuls of food to hundreds of Rainbow trout that are now living in the lake. If you are lucky to see it, they might even sail out of the water to catch an airborne treat, surprising visitors on board.

The Lost Sea - Boat ride underground cave lake in TN

The Lost Sea History

Hidden deep under a mountain in East Tennessee near the town of Sweetwater you’ll find The Lost Sea. The Guinness Book of World Records lists that The Lost Sea as America’s largest underground lake. The Lost Sea is actually part of a large, historic cave system called Craighead Caverns and has been known by man since the early days when the Cherokee Indians inhabited the area. The cave expands from the tiny natural opening at the side of the mountain into a series of huge rooms. Around 1927-28, artifacts were found almost a mile into the cave near a room now called “The Council Room,” including arrowheads, pottery, jewelry, and weapons, attesting to the fact that the Cherokees were using the cave and perhaps even meeting in this room.

An earlier animal visitor and still on display are some bones and tracks of a giant Pleistocene jaguar discovered in 1939. Possibly the poor animal lost his way and wandered until falling into a crevice.

In the 1820s, the first white settlers arrived in the Tennessee Valley and rediscovered the cave. The cave itself offered a constant 58° temperature which was perfect for refrigeration of food, so they used it for storing vegetables and potatoes.

The Lost Sea - Engraved date found
Only date found underground.

You can still see the authentic 1863 date, which was carbon tested and possibly put there by a confederate soldier’s torch. The Confederate Army used the cave to mine for saltpeter which was a necessary ingredient to manufacture gunpowder and they operated a mining operation during the Civil War.

For years, there were rumors of a large underground lake somewhere in the cave, but it was not discovered until 1905. A 13-year-old boy named Ben Sands discover the huge lake. His father, John Sands, had also explored parts of the cave earlier and had led others interested in seeing parts of the cave. Ben found a muddy opening 300 feet underground and wiggled through it. He found a room so large that his light wouldn’t let him see either the ceiling or the far wall. The room was also half filled with water. Ben would enjoy telling this story for the rest of his life about how he threw mud balls as far as he could but still didn’t hear anything but splashes in every direction he threw. Today, despite the best efforts of divers using modern exploration equipment, the full size of the lake is still not known. The part of the lake that can be seen is 800 feet long by 220 feet wide and over four acres.

Beneath the lake, divers have found a larger series of rooms which are completely filled with water. So far more than 13 acres of water have been mapped and no end to the lake has been found. Using a sonar device, one diver ventured into the dark water-filled rooms and took soundings in all directions and found nothing but more water. He had to hug the wall to make sure he could find his way back.

Inside the Lost Sea cave

The idea of developing the cave for visitors began in around 1915. In one of the upper rooms of the cave, a dance floor was installed. Another frequent activity were cockfights. Moonshiners also took advantage of the huge system of caves to produce their famous brew.

In 1927 a larger and easier entrance was opened up for visitors just below the natural one. The Tennessee Power Co. installed the first lighting system and interestingly the lighting of the cave helped to foster the early rural electrification in the surrounding area. In order to have electric service installed, farmers in the area helped in cutting poles and cooperated by providing right-of-ways on their land. Finally in December 1964 the development began in earnest and Lost Sea Caverns opened as an official tourist attraction.

Lost Sea Adventure Tours

As you visit the Lost Sea, your tour guide will share plenty of tales about the fascinating history of Craighead Caverns. You’ll walk through immense rooms down into the deepest reaches leading to the Lost Sea. The boat ride is part of the tour. It is a treat to see all the variety of cave formation including rare crystalline displays of Anthodites, also known as “cave flowers”. These beautiful and fragile, spiky clusters are found in very few caves around the world and because of their abundance in Craighead Caverns, the Lost Sea is designated by the United States Department of the Interior as A Registered National Landmark. This honor is only shared by unique geological areas such as Yosemite National Park, California and Cape Hatteras National Seashore, North Carolina.

Wild Cave Tour at the Lost Sea
A favorite tour for the boy scouts and others who like to see the wild side of the Lost Sea cave.

If you prefer a more “wild tour”, you can arrange to go on the Wild Cave Tour. You’ll need clothes that you won’t care to get dirty as you crawl through cave tunnels with your guide. This is favorite adventure of boy scout troops, my son described to me what it was like to crawl through places that it was hard to fit through, with the feeling of the whole mountain above him. You’ll see parts of the cave that regular visitors never get to see.

What to Wear to The Lost Sea

Since the cave is a constant 58 degrees, it is recommended that you wear a light jacket or a sweater. The humidity is very high which makes the temperature feel a little warmer. Wear comfortable walking or hiking shoes, the regular tour has wide sloping walkways but heels, flip-flops, or backless shoes are not recommended. The Lost Sea is a perfect adventure at any time of year. They are only closed on Christmas day.

Directions to The Lost Sea

Be sure to bring your camera and flash to the Lost Sea. You’ll want to take pictures home with you. Or visit their gift shop which has lots of memorable item. Our group delighted in the Lost Sea pens where the ship moved back and forth when you tilted it. All you need to do from Knoxville is take I-75 south to Highway 68, Exit #60, make a left turn and follow the signs. Call (423) 337-6616 for more information or visit The Lost Sea online.

The Lost Sea - tickets

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