Visiting The Lost Sea Adventure Is One Of The Most Unique Experiences In East Tennessee
Perhaps you’ve heard something about a huge cave boat tour in Sweetwater, TN, halfway between Chattanooga and Knoxville? It is a real thing, and it is totally worth going to see.
The Lost Sea is a large cavern containing the largest underground lake in the US. And you get to go on a glass bottom boat to explore. Guaranteed to be something fun and different from any other cave tour you have taken!
Visiting The Lost Sea Adventure is a fun time any day, but it is particularly perfect for cold winter days, hot and humid summer days, or rainy days in general.
This is my complete guide to the Lost Sea Adventure, from where and what it is, the super cool history of the cave, and practical information like ticket prices, the different tours available, and how long you will spend there.
Plus other handy need-to-knows like what to wear in a cave to stay warm, and most importantly, are there really blind fish in the lake?
Here’s everything to know!
Info At A Glance
Location
140 Lost Sea Rd, Sweetwater, TN 37874
7 miles off of I-75 on Hwy 68
1 hr 10 min from Chattanooga
50 min from Knoxville
1hr 30 min from Pigeon Forge
Tickets
$28.95 Adults
$16.95 Kids (4-12)
Open Everyday (except Christmas and Thanksgiving)
Time And Difficulty
The regular tour is 1 hour 15 minutes.
You walk 3/4 of a mile roundtrip and descend 140 ft underground on an inclined path. It can feel like a steep uphill on the way back.
The Lost Sea Adventure was a fond memory from my childhood spent in East Tennessee, going on school trips and summer days when it was too hot to be outside.
I am happy to say it is still a great experience for kids and adults alike and that the boat tour on the underground lake is still a thrilling and otherworldly experience.
What Is The Lost Sea? What Makes It Special?
The Lost Sea is part of the larger Craighead Caverns, a system of caves that extends from Sweetwater all the way north to Madisonville.
The Lost Sea is the largest underground lake in the United States (it is in the Guinness Book of World Records) and is the 2nd largest underground, non-subglacial, lake in the world. So pretty unique there.
It was designated a National Natural Landmark in 1973 because of the size of the lake and the abundance of “cave flowers,” a rare type of crystalline clusters technically called anthodites.
The underground lake that you tour is a little less than 5 acres (so about 3.5 football fields) but there are lots more caves below this one that are completely filled with water. No one is sure how far the water goes.
Besides the sheer size of the cave and the lake and the rare cave crystals, I also think the Lost Sea is special and worth visiting because there is some nifty history associated with it.
The History Of The Lost Sea – Jaguar Fossils, Civil War Graffiti, And Moonshine
Okay, bear with me for the history lesson because it has to do with much of what you will see on your visit. There is a lot to see on the tour of the cavern besides just the underground lake, although that is the undeniable star of the show!
Super Short Geologic History
The many caves and cave systems in east and middle Tennessee (over 10,000 found so far) are due to the abundance of limestone in the area. 250 million years ago, this area was covered by a shallow inland sea leading to the limestone formation.
Some 90 million years ago, the inland sea dried out as the land was uplifted and surface water began to trickle through the limestone bedrock, dissolving it and forming the caves found all over this part of Tennessee.
A Pleistocene Jaguar in the Lost Sea – the earliest known tourist to the cave
During the Pleistocene era about 20,000 years ago, a giant jaguar wandered into the cave and didn’t get out, leaving some super cool bones for humans to find in 1939.
You can see the bones and casts of its footprints in the Visitor Center (and some of its bones are now located in the American Museum of Natural History in NYC if you are ever up that way).
This jaguar was probably a bit bigger than a modern jaguar but the subspecies is now extinct.
Human History In The Lost Sea
The Cherokee
The Cherokee used the “Council Room,” a large cave near the entrance, as a meeting place, leaving behind archaeological artifacts like jewelry and weapons. Later, white settlers in the area used the caves as food storage, handy since the caves maintain a steady 58 degrees year-round.
Civil War History
Confederate soldiers mined saltpeter in these caves and also left behind graffiti for us to admire. The names and dates in black on the cave walls were made using ash from the soldiers’ torches which carbon dating has corroborated.
Only the names in black are historic, the names in white were scratched into the rock in modern times. It’s interesting to see that the “I was here” sentiment hasn’t changed much over the years.
*** Trivia Alert– Saltpeter is the old-fashioned name for potassium nitrate, an integral component of gunpowder. The saltpeter mined in caves primarily comes from bat guano (that’s the technical term for bat poop).
Craighead Caverns History Since the 1900s
The first credited discovery of the underground lake goes to a 13 year old boy, Ben Sands, in 1905. He crawled through a tunnel the size of a bike tire to reach the lake (this makes me freak out as a parent), but by the time he brought his Dad back to show him, the water levels had changed. They were unable to find the tunnel again.
The lake lay hidden for the majority of people until 1965, when the tiny passageway was blasted out to allow tourists down to the lake.
Previous entrepreneurs have tried a variety of enterprises in the caves. In the 1940s, there was an underground bar with a dance floor called the Cavern Tavern in one of the larger rooms in the cavern. (Which is an absolutely awesome name by the way.)
There were several moonshine operations (you’ll see an old moonshine still by one of the walkways) and even a mushroom growing operation once.
The government designated the caves as a fallout shelter during the Cold War, storing thousands of pounds of food down here, some of which can still be seen on the cave tour too.
What To Expect On A Tour Of The Lost Sea
Arriving At The Lost Sea Adventure
When you turn off Highway 68 into the entrance of The Lost Sea, the entrance drive takes you by several parking areas and a collection of buildings to your left and one building to your right. The building on the right is the ticket office and entrance to the caves.
There are two types of tours offered by the Lost Sea Adventure:
- Regular tour
- Wild Cave tour
Almost everyone takes the regular tour which lasts just over an hour and includes the boat ride on the underground lake.
The Wild Cave Tour is for the more adventurous folks and takes you crawling through small holes to explore the less visited parts of the cave. It is for larger groups (school, church, scouts, etc) and requires advanced notice.
You can buy your tickets online ahead of time for the regular tour, but you must still check-in at the ticket desk.
We highly recommend buying tickets ahead of time so you can pick your time. You can walk in and get tickets, especially in the less busy winter months, but you may have to wait an hour or so for the next tour to start.
The Regular Tour Of The Lost Sea Adventure
Details:
- This is the cave boat tour most people talk about
- Lasts 75 min, 3/4 mile loop walking path
- Descends 140 ft to the lake
The Regular Tour is the most popular tour of the Lost Sea and covers the main part of the cavern and the underground lake boat ride.
You will have a tour guide who will point out the interesting bits and explain the history and geology of the cave. (Which, of course, you are already familiar with having read my excellent history section above 🤣.)
You start at the entrance near the surface and make a loop through the cavern, with the boat tour in the middle. Along the way to and from the lake you will see stalactites, stalagmites, anthodites (the rare crystalline formations mentioned above), an old moonshine still, the Civil War graffiti, and a waterfall.
You will also experience total darkness for about a minute when they turn off the lights, which is a highlight for everyone.
The tour lasts about an hour and 15 min and you need to be fairly mobile to participate. It covers 3/4 of a mile round-trip as a loop through the cavern. You descend 140 ft down to the lake (and more importantly, 140 ft back up to the surface – this is the hardest part of the walk).
The walkway is wide and steeply sloped in sections but there are decent handrails to use. The cave has a clay surface on most of the paths so wear good shoes as it can get slippery because the cave has high humidity all the time.
The cavern is very large so claustrophobia shouldn’t be much of an issue on the regular tour unless you can’t stand the idea of being underground at all.
The Boat Tour On The Underground Lake
The boat ride lasts about 15 min and each large, flat- bottomed boat holds 15-20 people easily. Motion sickness isn’t generally an issue as the water is completely calm, leaving you feeling more like you are gliding rather than motoring across the water.
Remember, the visible portion of the lake is about the size of 3.5 football fields so it can hold several boats at once no problem.
What About The Fish?
The large, rainbow trout were added to the lake in the 60’s and 70’s in the hopes that they would find their way out, get caught, and the tags would be reported back so they would know where the outlets might be.
Turns out, though, that trout don’t like to swim in the dark so they would not leave the lit sections of the lake and we still don’t know where the water goes exactly.
The rainbow trout, which are restocked periodically, are fat and happy. They are frequently fed and fishing isn’t allowed so they will come right up to the boat looking for their treats.
You can watch them swim underneath the boat as well, through the glass panels in the bottom.
Check out the website for more information and pictures about the Regular Tour.
The Wild Cave Tour Of The Lost Sea
This extended tour of the caves is offered to groups only. It can be done as a daytime trip or an overnight camping excursion.
In addition to the regular tour, you will get to explore additional, harder-to-access cave rooms, such as where the jaguar bones were found.
Plus, you get to crawl through crevices and holes, so it is much more of an authentic spelunking experience.
Many of the kids I grew up with, including my siblings, did the overnight tour with the Scouts or a church group and all of them still refer to it as an awesome experience years later. Certainly, it is a one-of-kind campsite.
The Practical Details For Visiting The Lost Sea
Opening Hours
Open everyday except Christmas and Thanksgiving. Do check the website for changes – Prices and hours for the Lost Sea.
- Winter (Nov-Feb): 9am -5 pm
- Spring/ Fall (Mar & April /Sept & Oct): 9am- 6pm
- Summer (May-Aug): 9am-7pm (8pm in July)
Ticket Prices
Regular Tour: Adults $28.95/ Kids 4-12 $16.95/ Under 3 are free
Tips are encouraged for the guides, so you might want to bring along a few extra bucks.
Location Of The Lost Sea Adventure
The Lost Sea Adventure is in Sweetwater, Tennessee, about 50 minutes southwest of Knoxville or 1 hr 15 min northeast of Chattanooga. It is just 7.3 miles from Interstate 75, directly off of Highway 68.
Getting There
Take exit 60 from I 75, following the sign for Highway 68/ Sweetwater. Go east on Highway 68, through a collection of strip malls and fast food outlets. Once you cross Highway 11, though, you get to more picturesque farmland and rolling hills.
Look for the sign for The Lost Sea Adventure on your left about 5 miles after you cross Highway 11. It will take you about 10 min total from Interstate 75 to get to The Lost Sea.
Weather In The Lost Sea/What To Wear
Wear sturdy shoes with good traction. The pathways are packed dirt and due to the high humidity in the cave, they are always slightly slick.
We did not have anyone slip and fall but it could have easily happened several times. Use the handrails if needed.
It is a constant 58 degrees in the caves, so I would wear long pants or bring a light jacket. The high humidity keeps it a warm 58 though. It doesn’t seem cold at first but after about 30 minutes, you start to notice.
Especially if you are visiting in the summer, you will feel the difference, although that is a great thing when it’s 100 outside!
Some Handy Tips
Use the bathrooms right next to the ticket desk before your tour. It will be your last chance until the tour is over.
Be sure to check out the Pleistocene jaguar skull and footprints as well as the largest trout ever caught in the lake. Both are preserved in cases near the ticket desk.
What Else To Do At The Lost Sea Besides The Underground Tours
Besides the tours, you will also find a gift shop, sweet shop with ice cream, a glass blowing place, a cafe, a general store, gem mining, and a nature trail.
The gift shop is adjacent to the ticket desk in the main building. Everything else is located in the little collection of buildings, called the Lost Sea Village, which is across the street from the main building (where the ticket desk and cave entrance are).
The Lost Sea Village
With your ticketed admission, you can also visit the Lost Sea Village. The Village Cafe serves sandwiches and pit BBQ and has a covered picnic area attached. We brought our own picnic lunches and enjoyed them at these picnic tables.
The glassblower has lots and lots of pretty little ornaments that all looked incredibly breakable so we did not venture into it with the kids on our last visit.
A few things are closed in the off-season, especially on weekdays, such as the General Store and Sweet Shop. They are popular places to visit in the summer, though.
The gem mining was also nifty looking and looked to be a fun activity to keep the kids occupied while the parents sat at the nearby picnic tables.
The Nature Trail is just a 1/3 mile long and I wouldn’t get overly excited about it but it is good for a quick stretch of the legs.
The Lost Sea Village 
Gem Mining at the Lost Sea
Other Things To Do That Are In The Area
Visit Sweetwater, TN
10 min from The Lost Sea Adventure
Sweetwater is working hard to redevelop its Main Street and has some picturesque buildings along its main square.
You’ll find several antique shops, a gift store, clothing boutiques, and an old train car from the “Pelican Line” that ran through town, taking travelers from NYC to New Orleans.
If you are hungry, try Vittorino’s Cucina or Hunter’s Bakery and Cafe. If it is a great cup of coffee and a baked good you are after, try the Cup Runneth Over Coffeehouse.
For an afternoon ice cream treat, be sure to drop by the Sweetwater Creamery.
All of these restaurants are located around the main square in downtown Sweetwater. Parking is available there too.
If you need a playground break, the Sweetwater Recreation Park is just a half mile away from Main Street. You can drive there or you can take the greenway along Sweetwater Creek. There are 2 playgrounds: a big new blue one next to the soccer fields and a second one with a climbing net and swings next to the walking track.
Getting to Sweetwater
Downtown Sweetwater is just 10 min from The Lost Sea Adventure. Turn right on Highway 68, go back to Highway 11 and turn right again. From here it is just a mile until you come to downtown Sweetwater. (See the map above showing the location of the Lost Sea.)
You will see the gazebo and train car on your right as you come into downtown on Highway 11/ Main Street. There is plenty of public parking there.
Sweetwater Valley Farm
20 min from The Lost Sea Adventure / 10 min from downtown Sweetwater
If you love delicious cheese and lots of it, then this will be your happy place. Sweetwater Valley Farm is a huge dairy farm that makes a stunning variety of cheeses on site so you can tour the farm, learn about cheese, and sample to your heart’s content. Then buy a bunch to take home with you.
You could spend 30 min or 2 hours here, depending on your devotion to all things cheese and whether you take the tour of their state of the art robotic milking facility.
The gouda and fiesta cheddar are personal favorites but I would eat any of the cheeses from Sweetwater Valley Farms. So good.
To get to Sweetwater Valley Farm, turn right on Hwy 68 from The Lost Sea. Then turn right on Hwy 11, heading towards downtown Sweetwater. Stay on Hwy 11 for 8 miles until you see the big white, brick entrance to the farm.
The shop and cafe are open Tues – Sat from 9am – 5pm. The cafe serves sandwiches 11 -3 and milkshakes all day. The menu is basically all things cheese (shocking, I know) from grilled cheese to cheese and meat melts and pimento cheese. There is a kids menu also.
Tours of the dairy are every hour from 10 am until 3pm and take about an hour. Tickets are $16 adults and $10 kids 3-11 and you can buy them ahead of time online. (And I would think twice about kids unless they are really into milking. I found it fascinating but the younger kids were over it by about 30 minutes in.)
Cherohala Skyway
30 min from The Lost Sea Adventure
A national scenic byway, the 40+ miles of the Cherohala Skyway (see our Guide) takes you from Tellico Plains, TN to Robbinsville, NC and to some million dollar views along the way.
Simply turn left from the Lost Sea onto Highway 68 and follow it for 17 miles until you turn left onto Highway 165, following the signs for Tellico Plains, Cherohala Skyway, and Indian Boundary.
Start in Tellico Plains with some goodies from the ever excellent Tellico Grains Bakery (the sandwiches, the coffee, the loaves of bread—it’s all amazing). Then detour out to the gorgeous Bald River Falls first for some Instagram-worthy shots before getting on the the Skyway.
Be sure to stop at Huckleberry Knob on the Skyway. It is a 1.25 mile hike to a gorgeous bald with 360 views of the Smokies.
Check out our Cherohala Skyway Guidey for all the information and tips you need to tour one of America’s most scenic drives.
I hope you enjoy your time at the Lost Sea Adventure. It certainly is one of the most unique experiences in the area and one that has always made an impression on the kids.
Please check out our website, Knoxville Backyard & Beyond to find even more ideas for family adventures big and small in East Tennessee!
Happy Trails – Amanda
We had an hour in the cave….our guide went at such a fast pace, he was always way ahead of us. Didn’t have time to take photos and ask questions along the way. The guide talked very fast in a monotone voice …. Very hard to understand. It was like a road race! We were there Monday, 8/25/2025. Needless to say, we were very disappointed.
Oh no! I hate to hear that. I wonder if you reach out to them, they would comp you a return visit. That is frustrating when you feel like you are missing out on the experience.- Amanda