Georgetown, Texas: Inner Space Caverns

Cave exposed by 1960s roadwork and turned into a commercial attraction -- features the "Lake of the Moon," and the "Flowing Stone of Time."
4200 S IH 35, Georgetown, TX
I-35, Exit 259, north of Austin.
Summer M-Sa 9 am - 6 pm, Su 10 am - 6 pm, other M-F 9 am - 4 pm, Sa 10 am - 5 pm, Su 11 am - 5 pm. (Call to verify)
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Visitor Tips and News About Inner Space Caverns

Reports and tips from visitors and Roadside America mobile tipsters. Some tips may not be verified. Submit your own tip.

Inner Space.

Inner Space Caverns

If you go late on a Monday to Inner Space Caverns, you may end up with a personal one on one tour -- we did -- was awesome!

[Annie, 06/15/2016]

Formations in Inner Space Caverns.

Inner Space Caverns

Just visited this cavern again and it's well worth the stop. The tour guides are friendly and very knowledgeable. If you phone before you arrive, they'll tell you which hours of that day should help you avoid mass tour groups of elementary school kids. Well-stocked gift shop. Depending on the time of year, you may get to see hibernating bats. They do turn off all the lights momentarily at one point during the underground tour, so be prepared for DARK. Wear comfortable shoes; it's a walk. Photography is allowed.

A staff member confirmed that comedian Bill Engvall, famous for his "Here's your sign" routine, did indeed work at Inner Space Caverns many years ago when he was attending college. Engvall stated this in his 2007 autobiography, Just a Guy, but he provides no details of the experience.

[Matt J. McCullar, 02/09/2008]

Discovery Hole, Inner Space Caverns.

Inner Space Cavern

I have visited this cave many times in the last 35 years. I have three Highway Department photos dated March 25, 1966, showing the workers entering the cavern at the time of discovery. It has declined over the years, due to flooding and loss of some of the original equipment and recordings.

Still, it is an awesome experience. The temperature is 72 year round and very humid. Drops of calcium-filled water will drip on you, there are some low spots in the ceiling, and some slippery spots. Wear tennis shoes and clothes you wouldn't mind getting stained. Lots of fun for kids of all ages.

[Jeff, 03/13/2007]

And kids of all ages, please note: you don't enter the cave by sliding down that pole.

Drill hole that discovered Inner Space Caverns.

Inner Space Caverns

Anyone driving south on I-35 towards Austin, Texas won't have trouble finding Inner Space Caverns. Their billboards used to scream at you for dozens of miles. Many years ago, however, I recall their signs didn't tell you what "Inner Space" was. You saw the name, but that was it. At the time I didn't know if it was a nightclub, a restaurant, or what. Apparently a great many other travelers were just as confused and therefore failed to stop at the place. Finally management got wise and added "Caverns" to the signs, which I think has greatly increased attendance.

I took the guided tour about five years ago and it's well worth the price. A railway-type car lowers you into the caverns, and the walking tour takes about an hour. I'm 6'4" and had to duck my head more than a few times. Take your camera, and wear comfortable shoes.

South Texas is eaten up with underground caverns but most of them are on (under) private land. Inner Space Caverns was discovered in the early 1960s when the Texas Highway Department was laying out Interstate 35. To their surprise, the drill bit fell into empty space; a worker was lowered into it with a flashlight to take a look around. Many other caverns have been known about since ancient times, but this guy was the first human being in history to enter Inner Space Caverns. It had no natural openings to the outside world. You can still see that original hole in the ceiling of one of the underground rooms when you take the tour today. I-35 got moved over sideways a little bit as a result, and in fact you can faintly hear the traffic from some parts of the caverns.

[Matt J. McCullar, 08/13/2006]

Lake of the Moon - vintage shot.

Inner Space Caverns

When we last visited, Inner Space was doing a brisk business, its alien eye sign visible from the interstate. At least 15 employees in identical uniforms scurried around the gift shop or prepared to take tour groups down to the cave via the entrance tram.

Inner Space Caverns was accidentally discovered in 1963 by the Texas Highway Department, which was clearing a path for the new interstate. As a result, the cave arrived as a tourist attraction in the 1960s in its pristine state. The cave owners, in conjunction with the U. of Texas, unearthed many fossils of mastodons, sabre tooth tigers and other monsters of the Stone Age. Some are displayed near the Bone Sinks.

August 2000 flooding destroyed "sound 'n' light "shows for the Lake of the Moon and the Flowing Stone of Time. The Lake show was a sort of aerie faerie poem, and the Flowing Stone of Time was the voice of God describing the creation of creation. We'll have to dig out our video recording...

[ Team, 01/11/2004]

Nearby Offbeat Places

Statue of Three-Legged WillieStatue of Three-Legged Willie, Georgetown, TX - 2 mi.
Doughnuts Larger Than Your HeadDoughnuts Larger Than Your Head, Round Rock, TX - 7 mi.
Hutto Hippo StatuesHutto Hippo Statues, Hutto, TX - 9 mi.
In the region:
Round-Headed Artist with Paintbrush, Austin, TX - 20 mi.

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