Located in the Ilocos region, Ilocos Sur is known for its heritage sites like Calle Crisologo. Ilocos Sur has a total area of 2,596 square kilometers and comprises 32 municipalities, 2 component cities, and 768 barangays. Its capital is Vigan. Places to visit in Ilocos Sur are Calle Crisologo, Syquia Mansion Museum, and Sta. Maria Church.
| Location | Ilocos Sur ZIP Code/Postal Code | Phone Area Code |
| Alilem | 2716 | 77 |
| Binayoyo | 2708 | 77 |
| Bantay | 2727 | 77 |
| Burgos | 2724 | 77 |
| Cabugao | 2732 | 77 |
| Candon | 2710 | 77 |
| Caoayan | 2702 | 77 |
| Cervantes | 2718 | 77 |
| Galimuyod | 2709 | 77 |
| Gregorio del Pilar | 2720 | 77 |
| Lidilda | 2723 | 77 |
| Magsingal | 2730 | 77 |
| Nagbukel | 2725 | 77 |
| Narvacan | 2704 | 77 |
| Quirino | 2721 | 77 |
| Salsedo | 2711 | 77 |
| San Emilio | 2722 | 77 |
| San Esteban | 2706 | 77 |
| San Ildefonso | 2728 | 77 |
| San Juan | 2731 | 77 |
| San Vicente | 2726 | 77 |
| Santa | 2703 | 77 |
| Santa Catalina | 2701 | 77 |
| Santa Cruz | 2713 | 77 |
| Santa Lucia | 2712 | 77 |
| Santa Maria | 2705 | 77 |
| Santiago | 2707 | 77 |
| Santo Domingo | 2729 | 77 |
| Sicay | 2719 | 77 |
| Sinait | 2733 | 77 |
| Sugpon | 2717 | 77 |
| Suyo | 2715 | 77 |
| Tagudin | 2714 | 77 |
| Vigan | 2700 | 77 |
Go back to the main article: ZIP Codes in the Philippines: The Complete List
