The Texas Water Development Board classifies the karstic Edwards and Trinity aquifers as major sources of water in south-central Texas. To effectively manage the water resources in the area, detailed maps and descriptions of the geologic framework and hydrostratigraphic units of the aquifers outcropping in Hays County, Tex. are needed. In 2016 and 2018, the U.S. Geological Survey, in cooperation with the Edwards Aquifer Authority, mapped the geologic framework and hydrostratigraphy of the Edwards and Trinity aquifers within Hays County, Tex. at 1:24,000 scale. These digital data accompany Clark, A.K., Pedraza, D.E., and Morris, R.R., 2018, Geologic framework and hydrostratigraphy of the Edwards and Trinity aquifers within Hays County, Texas: U.S. Geological Survey Scientific Investigations Map XXXX, pamphlet XX p., 1 sheet, scale 1:24,000, https://doi.org/10.3133/simXXXX (In Press).