The shortest driving distance is 275 miles.
Depending on which route you take, Google Earth cites the minimum distance as 274 miles.
the travle time between Brownsville Tx to San Antonio Tx is about 430 miles. of course this depends on what part of SA you wish you visit...
San Antonio, TX
Brownsville, TN
It is 277 miles and an estimated 4.75 hours of driving time according to Google Maps.
It is 65.60 miles according to MapQuest.
It is 128.53 miles according to MapQuest.
It is 250.82 miles according to MapQuest.
It is 437.60 miles accoording to MapQuest.
Carlsbad, NM to San Antonio, TX is about 450 miles by road.
It is 114.25 miles according to MapQuest.
It is 279.02 miles accordiing to MapQuest.
It is 347 miles accordiing to Google Maps.