A look at one of Austin’s lesser known caves called Sunset Valley Cave.

Did you know Sunset Valley has a secret cave? Sunset Valley Cave is one of Austin’s lesser known caves which not many people know about. This news article will explain the environmental features of Sunset Valley Cave.


Sunset Valley Cave is a cave located in the Indian Grass Prairie Preserve along Williamson off of Brodie Lane and Home Depot Boulevard. The cave is located along northern edge of the area. Sunset Valley Cave aka Goat’s Head Cave is a recharge feature for the Edwards Aquifer recharge zone. This cave is a sensitive karst feature which is home to a variety of invertebrate species. The cave is composed of two main chambers located approximately 700 feet above sea level. (Ref: https://www.sunsetvalley.org/home/showpublisheddocument/250/637735384638870000)

Sunset Valley Cave is bisected by Williamson Creek, which is composed of Mixed Alluvial Land. Mixed Alluvial Land is comprised of beds of exposed limestone and gravelly alluvium (Ref: USDA, 1974).

Sunset Valley Cave developed as vertical shafts from porous limestone several million years ago. This karst formation is typical of many throughout Central Texas. The karstified limestone acts as an aquifer where water can be stored and later extracted by humans. Dissolution associated with karst development in central Texas limestone has created a complex underground water flow network that includes caves large enough for humans to access. Rainwater travels through the network, controlled by the Balcones fault system, until it reaches the water table. (Ref: https://www.geocaching.com/geocache/GC48Q5D_sunset-valley-is-sinking?guid=007eb7a0-f4c9-47f4-b77d-50cce146b2e3)

Sunset Valley Cave has vuggy and burrow porosity. Permeability associated with burrowed zones, breccia and cavern porosity. Permeability associated with collapsed zones resulting from dissolution of evaporites. Fracture porosity and permeability associated with faulting. (Ref: https://www.twdb.texas.gov/publications/reports/contracted_reports/doc/94483045.pdf)

A majority of Sunset Valley Cave is composed of Tarrant and Speck soils. Tarrant soils are well-drained clay soils found atop limestone. Speck soils are reddish brown and also overlay a limestone substrate out of vuggy and burrow porosity. Limestone and clay compose a majority of this cave. (Ref: https://sunsetvalleytx.govoffice2.com/vertical/sites/%7B8963FD9D-CEFE-410A-A38B-1611D53E7AA1%7D/uploads/%7BFE34051C-72F3-482E-BF6A-48C94AC66340%7D.PDF)


However Sunset Valley Cave is safe or legal to explore without getting permission from the City of Sunset Valley. It’s neat to walk by it near the trail. Sunset Valley Cave is supposedly home to lots of wildlife. (Ref: https://austin.com/indian-grass-prairie-preserve-and-sunset-valley-nature-area/)

The reason why it is not safe or legal to explore Sunset Valley Cave is because of environmental sensitivity. Sunset Valley Cave is located in the Edwards Aquifer recharge zone which is an environmentally sensitive area. If there are signs of human activity in the cave, then that means water from the Edwards Aquifer recharge zone would be polluted. 2 million people in Central Texas rely on Edwards Aquifer for drinking water.  

Sunset Valley Cave is located at 5886 Brodie Lane, Austin, Texas, US 78745.