Trans-Pecos Texas Ranges | Level 4 (Parent) |
         El Paso Ranges | Level 5 (Sibling) |
         Van Horn Area | Level 5 (Sibling) |
         Presidio County Area | Level 5 (Sibling) |
         Guadalupe Mountains | Level 5 (Sibling) |
         Delaware Mountains | Level 5 (Sibling) |
         Davis Mountains | Level 5 (Sibling) |
         Glass Mountains | Level 5 (Sibling) |
         Big Bend Ranges | Level 5 |
                 West Big Bend Ranges | Level 6 (Child) |
                 Del Norte Mountains | Level 6 (Child) |
                 Woods Hollow Mountains | Level 6 (Child) |
                 Chalk Mountains | Level 6 (Child) |
                 Santiago Mountains | Level 6 (Child) |
                 Tinaja Mountains | Level 6 (Child) |
                 Christmas Mountains | Level 6 (Child) |
                 Rosillos Mountains | Level 6 (Child) |
                 Sierra del Carmen | Level 6 (Child) |
                 Chisos Mountains | Level 6 (Child) |