Del Rio lies on the northwestern edges of the Tamaulipan mezquital, also called the South Texas brush country. It is also near the southwestern corner of the Edwards Plateau, which is the western fringe of the famous, oak savanna-covered Texas Hill Country; that area is dotted with numerous small springs; one of these is the San Felipe Springs, which provides a constant flow of water to San Felipe Creek. The creek supplied fresh water for drinking and irrigation to early settlers of Del Rio, and the springs are still the town's water supply.