This highly detailed map from the U.S. Geological Survey covers the Edwards Aquifer Recharge Zone from Austin to northwest of Uvalde and depicts the complicated geology of the area along with counties, cities and highways.
Don't need the printed map? Click HERE
to download the PDF file FREE! (if it opens in an Adobe Reader (Acrobat) window, click the "Save a copy" icon or click File->Save a copy; Or, you can just right-click on the link and choose "Save target as..").