| Locality | Post Code |
|---|---|
| Blanca, Costilla | 81123 |
| Chama, Costilla | 81126 |
| El Rito, Costilla | 81152 |
| Forbes Park, Costilla | 81133 |
| Fort Garland, Costilla | 81133 |
| Garcia, Costilla | 81152 |
| Jaroso, Costilla | 81138 |
| Los Fuertes, Costilla | 81152 |
| Mesita, Costilla | 81152 |
| San Francisco, Costilla | 81152 |
| San Luis, Costilla | 81152 |
| San Pablo, Costilla | 81152 |
| San Pedro, Costilla | 81152 |
| Sangre De Cristo Ranches, Costilla | 81133 |
| Wildhorse Mesa, Costilla | 81152 |