Inner Space Cavern, Georgetown

Inner Space Cavern is a karst cave located in Georgetown, Texas. The cavern was carved by water passing through Edwards limestone. The cavern is estimated to be 90–100 million years old but were only open to the surface since the late Pleistocene period 20,000–45,000 years ago.

There were several large openings to the caverns during the Ice Age, and evidence of several skeletons of prehistoric Ice-Age animals including a baby mammoth, giant sloth and the saber-toothed tiger have been found in the cavern; many were trapped in the cavern after they fell through the opening, unable to escape, and others drowned in thick, quicksand-like mud at the bottom of watering holes. Some filled-in sinkholes have been found, including the prehistoric entrance to the cavern. All natural entrances closed approximately 14,000 years ago.

The cavern was discovered by the Texas Highway Department in 1963 during the construction of an overpass for Interstate 35. The cavern was mapped for the first time by the Texas Speleological Association in 1963; since then, several miles of the cavern's passage have been surveyed, with many sections of the cavern remaining unexplored, due to filled-in areas being blocked.

The cavern was opened to the public in 1966. Three different levels of tours are available, ranging from a basic guided tour to guided spelunking, with over 1.2 miles of passage being open to the public. However, non-public passages are well-guarded and independent exploration is not allowed. Apart from the main entrance, which was created by dynamite blasts, one of the original 18-inch diameter drilled holes serves as an emergency entryway/exit and a means for ventilating the cavern.

Plan your visit to Inner Space Cavern and a wealth of other attractions, well-known and undiscovered, using our Georgetown road trip planner.
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