Founded in 1858, Duval County is one of 254 counties in the state of Texas. Historically, Duval County was formed from Live Oak County, Nueces County and Starr County. The city of San Diego is the county seat. With FIPS code of 131, Duval County has a population of 9,756 and area of 1,793 square miles (4,644 km2).
List of all cities in Duval County, TX alphabetically
| City/Town | Postal Code | Area Code |
| Benavides, TX | 78341 | 361 |
| Concepcion, TX | 78349 | 361 |
| Cruz Calle, TX | 78349 | 361 |
| Freer, TX | 78357 | 361 |
| Ramirez, TX | 78376 | 361 |
| Realitos, TX | 78376 | 361 |
| Rios, TX | 78349 | 361 |
| Rosita, TX | 78384 | 361 |
| San Diego, TX | 78384 | 361 |
| Sejita, TX | 78376 | 361 |
| Seven Sisters, TX | 78357 | 361 |