Click the underlined County to visit their website
| COUNTY | DATE FORMED | PARENT COUNTY | COUNTY SEAT |
| COKE | 1889 | TOM GREEN | ROBERT LEE |
| CONCHO | 1858 | BEXAR | PAINT ROCK |
| CROCKETT | 1875 | BEXAR | OZONA |
| GLASSCOCK | 1887 | TOM GREEN | GARDEN CITY |
| IRION | 1889 | TOM GREEN | MERTZON |
| KIMBLE | 1858 | BEXAR | JUNCTION |
| MENARD | 1858 | BEXAR | MENARD |
| REAGAN | 1903 | TOM GREEN | BIG LAKE |
| RUNNELS | 1858 | BEXAR, TRAVIS | BALLINGER |
| SCHLEICHER | 1887 | BEXAR | ELDORADO |
| STERLING | 1891 | TOM GREEN | STERLING CITY |
| SUTTON | 1887 | BEXAR | SONORA |
| TOM GREEN | 1874 | BEXAR | SAN ANGELO |