| Locality | Post Code |
|---|---|
| Altamira, Mercedes | B6601 XAB |
| Barrio General San Martin, Mercedes | B6000 XAL |
| Comahue Oeste, Mercedes | B6601 XAC |
| Goldney, Mercedes | B6614 XAA |
| Gowland, Mercedes | B6608 XAA |
| Kilometro 125, Mercedes | B6600 XAC |
| La Valerosa, Mercedes | B6601 XAD |
| La Verde, Mercedes | B6601 XAE |
| Manuel José García, Mercedes | B6608 XAB |
| Mercedes, Mercedes | B6600, B6602 |
| San Jacinto, Mercedes | B6600 XAD |
| Seminario Pio Xii, Mercedes | B6600 XAB |
| Tomás Jofré, Mercedes | B6601 XAF |