Visit to Inner Space Cavern

If you dig deep enough in central Texas you might just find a big hole in the ground. That’s what happened back in 1963, when the highway department was taking core samples of bedrock limestone in preparation for the construction of I-35. In Georgetown, 25 miles north of Austin, the drill went clear through the limestone and hit an air pocket. After widening the 40-foot-deep hole to a skinny 24 inches, they sent a man with a flashlight down on the drill bit to investigate.

This is what he found.

Inner Space Cavern had been a sealed cave for 10,000 years, with only a few sinkholes here and there to betray its presence—“bone drops,” where prehistoric animals like woolly mammoth fell to their deaths; their remains have been found in the cave. Over time the sinkholes had filled in, and no humans had ever entered. After the highway department discovered it, road construction continued nearby. Meanwhile, the privately owned cave opened to the public in 1966. You can hear the faint rumble of I-35 traffic from deep inside the cavern in certain places.

Thanks to the steady dripping of calcareous water, the cavern has a number of beautiful formations. I was delighted by these “soda straws,” formed by calcium-filled water dripping for eons from the ceiling.

Enormous stalactites and stalagmites bridge the gap between floor and ceiling.

A close-up of the soda straws, still dripping and lengthening at an infinitesimally slow pace.

For anyone who’s interested, I took these photos on my point-and-shoot’s Sport setting, which creates a grainier image but helps reduce blurriness from a hand-held in dim lighting conditions. No tripods are allowed, and to preserve the cave you aren’t allowed to touch anything, which means you can’t brace your camera. I refrained from using my flash, which I feared would flatten everything out and overexpose the white formations, and relied instead on the dramatic artificial lighting in the cave.

Unfortunately, without people in the pictures, it’s very difficult to get a sense of scale. Well, that just means you’ll need to go for a visit yourself. At a constant 72 degrees F, it would make an idyllic diversion for a hot summer day.

All material © 2006-2009 by Pam Penick for Digging. Unauthorized reproduction prohibited.

20 Responses

  1. Diana Kirby says:

    Great photos, Pam. Were you there on a class trip? It’s on our planner for August when the air is unbearable outside!

    Yes, I was a chaperone for my daughter’s class. August will be a good time to enjoy the cool cave air. —Pam

  2. Kim says:

    What a lovely place. I have always been fascinated by caves and caverns, and this one is spectacular. Maybe I should revisit the not-so-far Crystal Grottos in Boonesboro, MD. Sounds just the thing for a hot summer day. Thanks for sharing!

  3. Really good storytelling, Pam, about how the cave was discovered.~~Dee

  4. Jenny B says:

    Inner Space Cavern is amazing. It makes me wonder how many of these systems there are that have never been discovered. Your pictures came out great. What kind of camera do you have?

    Thanks, Jenny. It’s a two-year-old Canon Powershot S3 IS. —Pam

  5. Randy says:

    Very good photos Pam and your right a flash would have washed them out. Excellent skills on your part.

  6. Nicole says:

    Very lovely tour and pics. In Barbados there is Harrison’s Cave which is very similar and in 2006 I visited the limestone cave at Halong Bay, Vietnam.

  7. Brenda Kula says:

    I could live with those cool temps, just not in a cave! Isn’t it miraculous, though, this space hidden by time.

  8. Sue says:

    So pretty! Did you see the cave bacon? (It’s a rock formation that looks like bacon, before all the carnivores head cavewards). I’m interested in the camera setting, that would come in handy in a lot of situations.

    I love the cave bacon! It really does resemble bacon. Unfortunately, I didn’t get any pics of it. —Pam

  9. Great pictures. Haven’t been there in years. But, things change slowly in caves.
    Using the sport setting is such a good idea…fast shutter speed. That would work for more than sports, it seems. Thanks for that tip.

  10. Gail says:

    Thanks for the photo information Pam…goods point to keep in mind! The cave is wonderful, on a hot day it must feel great. gail

  11. Robin says:

    Pam, thanks for the reminder of this cool park so close to home. And in August, that 72 degrees will feel most wonderful – I think I’ll go then.

  12. Tatyana says:

    Out of this world. I will show your pictures to my boys. Thank you Pam!

  13. Uhm…puts your blog name ‘digging’ in a whole new light!

    Luckily, I didn’t have to dig this hole in the ground. ;-) —Pam

  14. Les says:

    Looks like a “cool” place. I hope all of the kids behaved. We have several caverns in Va., but the most famous is Luray Caverns. It hovers around 54 degrees, has an organ that makes the rocks sing by striking them with a mechanical hammer, and its most popular formation looks like two sunny side up fried eggs. The last time I was there, my son was 4 at the time. He was on overload as we were leaving and had a total nuclear meltdown. I had to drag him out of the gift shop kicking, screaming and flailing about just as a bus of Japanese seniors were pulling up. They got a good show.

    It’s always good to remind older people about the joys of young parenthood, just in case they’ve forgotten. ;-) That cave sounds pretty cool though. —Pam

  15. Germi says:

    You have just inspired me to plant as many vertical cactus in my front yard as I can afford! THAT’S what it needs! It’s going to be the STALAGMITE GARDEN!!! Thank you thank you thank you PAM! I always come away from your blog postings with a head full of ideas – love it!

    I love caves, having grown up there in South Texas and having them right in my backyard. I miss the majesty. Next time I’m down in those parts, I’m heading for the caves!


    A stalagmite garden would be something to see, Germi. Do it! —Pam

  16. Lola says:

    Thanks for the tour Pam. The pics were fantastic. I’ve been in caves before but did not know that there were any in Tx.

    Central Texas is full of caves, thanks to all the limestone we have. Spelunking is a popular activity around here. —Pam

  17. Jenny says:

    You certainly do some fun things with your children. Beautiful photos which makes me think it may be worth a visit. Someone told us that the Caves of Sonora are also great but we always seem to be rushing by there on our trip,s with no time to stop. Years ago we went to Carlsbad Caverns which have to be the ultimate big cave experience.

    Inner Space is worth a visit, Jenny, although it’s not as impressive as Carlsbad, which we saw about five years ago on the way to the Grand Canyon. Last summer we toured Mammoth Cave in Kentucky, which is also a must-see though it doesn’t have a lot of formations, just size.

  18. Lisa at Greenbow says:

    How interesting Pam. I bet it does feel good to be in there on a hot summers day. I would think it eerie to hear the rumble of traffic while in there.

    Even eerier was the rumble of a passing train, which you can hear not far from the entrance of the cave. It really sounded like an earthquake, even after our guide explained what it was. —Pam

  19. We’ve taken visitors to Inner Space Caverns – it’s fun to see them again through your wonderful photos, Pam. We like caves, too – saw Mammoth Cave as newlyweds on our honeymoon and have added caves in KY, MO, WI, TX and SD to the list. I can’t remember if you’ve shown us Longhorn Caverns in Burnet, but they’re sure nice on a hot day and Wondercave in San Marcos is a wacky, touristy attraction. Philo was able to go to Carlsbad but I missed that trip. I hope Jenny gets the chance to stop at Caverns of Sonora – absolutely breathtaking.

    Weather forecasters are threatening us with 100°F by Tuesday – these caves are sounding better and better!

    Annie at the Transplantable Rose

  20. Liz says:

    We went to Inner Space Caverns 20+ years ago. My son was about 6 and my daughter was about 3. It was her extremely independent and don’t mess with me stage. She insisted on wearing her sunglasses in the cave the whole time!