Post Offices List in Costilla County, Colorado:
| Fort Garland Post Office | 313 Highway 159, Fort Garland, CO 81133 |
| Jaroso Post Office | 111 Costilla Rd, Jaroso, CO 81138 |
| San Luis Post Office | 13 9th St, San Luis, CO 81152 |
| Blanca Post Office | 406 Smith St, Blanca, CO 81123 |