The cavern was discovered accidentally during the core drilling phase for a bridge pier foundation for I-35.
The cave floor contains fossilized bones of animals that roamed the area during the Pleistocene epoch.
The cavern is a 'living' cave, meaning moisture is still active and creating new formations.
The temperature remains consistent regardless of surface weather conditions.
The cave system includes several large chambers, such as the 'Hall of the White Giants' featuring massive flowstone formations.
Inner Space Cavern is a living limestone cave system in Georgetown, Texas, originally discovered by the Texas Highway Department in 1963 during the construction of Interstate 35. The cavern features extensive stalactite and stalagmite formations, including rare soda straws and flowstone deposits. Visitors access the underground chambers via a cable-driven train ride that descends into the cavern entrance. The site maintains a constant natural temperature of approximately 72 degrees Fahrenheit year-round. Paleontological excavations have unearthed the remains of prehistoric animals, including mammoths, scimitar-toothed cats, and peccaries, within the cave sediment. Tours are led by trained guides who navigate a series of paved walkways through the subterranean rooms. The cavern remains geologically active with ongoing water seepage contributing to mineral buildup. It is one of the best-preserved caves in Texas due to the minimal exposure to external air flow prior to its discovery.
The Hall of the White Giants features the most dramatic and largest flowstone formations in the cavern.
Wear comfortable, closed-toe walking shoes with good traction as paths can be slippery.
Bring a light jacket if you are sensitive to consistent temperatures.
Arrive early during peak summer months and weekends to avoid longer wait times for tours.
Attempting to touch the fragile rock formations or bringing bulky bags that might bump into cave walls.
Operates daily year-round, but may close for certain major holidays.
Touching the cave formations is strictly prohibited as oils from human skin can stop growth.
