The main attraction, the Devil's Sinkhole, is a National Natural Landmark that houses one of the state’s largest colonies of Mexican free-tailed bats. This enormous vertical cavern is thought to be the largest single-chamber cavern in Texas. The opening is a shaft approximately 50 feet wide that drops 140 feet into the cavern. Here, the shaft balloons out to a diameter of over 320 feet and reaches a total depth of over 350 feet. From late spring through early fall the sinkhole provides an amazing venue to witness over 3 million bats stream out into the evening sky.

Evening bat emergence tours, day tours to see the sinkhole, nature hikes, and even morning bat return flight tours bring visitors to the sinkhole and beyond to explore this unique piece of the Edwards Plateau. The 1,860-acre natural area is wild and mainly undeveloped. On your visit you can find remnants from the ranching past, trails for guided hikes, and two bird blinds for bird watching. At the sinkhole itself you can step out over the chasm onto the viewing platform and peer down into the depths below; the platform is wheelchair accessible. To protect this sensitive natural resource, visitors are not allowed to enter the sinkhole.