San Antonio anchors south-central Texas from its position along the Balcones Escarpment, where Hill Country limestone meets coastal plains. The metro area extends from Boerne and Bulverde in the northwest through Stone Oak and Alamo Ranch to the Medical Center corridor, reaching south past Brooks City-Base toward Southton and east through Converse and Universal City near Randolph Air Force Base. Five military installations—including Fort Sam Houston and Lackland Air Force Base—form the backbone of the local economy alongside the Texas Medical Center, the second-largest such complex in the nation, and a growing cybersecurity sector. The city's service area follows major corridors along I-10, I-35, and Loop 1604, serving both long-established neighborhoods near downtown and rapidly expanding suburbs in Bexar and northern Comal counties.