Welcome. Where is South Texas? Let me see... Wherever the the best tacos and tamales are to be had. This of course includes the Alamo (and Mission Trails), the Island (both Padre and South Padre), along the Rio Grande (RGV!), the Streets of Laredo, from the Briscoe Ranch to the King Ranch, El Aguilón (Eagle Pass) and the crossroads of Victoria (we didn't forget about you). Wherever there is hunting of whitetail deer or whitewing doves, and also fishing of bass or crappie in Falcon Lake to snapper/trout/flounder in the Gulf of Mexico. I almost forgot about those delicious Poteet Strawberries.
Basically, anywhere you call home. (If unsure, Wikipedia: South Texas is a region of the U.S. state of Texas that lies roughly south of—and including—San Antonio. The southern and western boundary is the Rio Grande, and to the east it is the Gulf of Mexico. )