| Name | What | Region | Country | Lat | Long | Elev Ft. | Pop Est |
| Maas-Asin | city | Province of Ilocos Sur | Philippines | 17.6891667 | 120.4727778 | 278 | 47352 |
| Mabatano | city | Province of Ilocos Sur | Philippines | 17.1377778 | 120.6161111 | 1738 | 7653 |
| Mabatano | city | Province of Ilocos Sur | Philippines | 17.2 | 120.6166667 | 1312 | 7737 |
| Mabec | city | Province of Ilocos Sur | Philippines | 16.9833333 | 120.7 | 1732 | 6374 |
| Mabilbila | city | Province of Ilocos Sur | Philippines | 17.5 | 120.4333333 | 108 | 32500 |
| Mabilbila | city | Province of Ilocos Sur | Philippines | 17.51 | 120.4447222 | 160 | 58129 |
| Mabilbila Norte | city | Province of Ilocos Sur | Philippines | 17.51 | 120.4447222 | 160 | 58129 |
| Mabilbila Sur | city | Province of Ilocos Sur | Philippines | 17.5 | 120.4333333 | 108 | 32500 |
| Macaoayan | city | Province of Ilocos Sur | Philippines | 17.3261111 | 120.5122222 | 75 | 25605 |
| Macawayan | city | Province of Ilocos Sur | Philippines | 17.3261111 | 120.5122222 | 75 | 25605 |
| Madarang | city | Province of Ilocos Sur | Philippines | 17.15 | 120.55 | 265 | 18570 |
| Madayao | city | Province of Ilocos Sur | Philippines | 17.0833333 | 120.6166667 | 2424 | 5493 |
| Magno | city | Province of Ilocos Sur | Philippines | 17.5 | 120.4 | 0 | 23196 |
| Magsingal | city | Province of Ilocos Sur | Philippines | 17.685 | 120.4244444 | 75 | 46641 |
| Magun | city | Province of Ilocos Sur | Philippines | 16.9819444 | 120.6841667 | 2624 | 6374 |
| Magur | city | Province of Ilocos Sur | Philippines | 16.9819444 | 120.6841667 | 2624 | 6374 |
| Mainganay | city | Province of Ilocos Sur | Philippines | 17.3833333 | 120.4833333 | 45 | 47927 |
| Mainganay Norte | city | Province of Ilocos Sur | Philippines | 17.3833333 | 120.4833333 | 45 | 47927 |
| Mainganay Sur | city | Province of Ilocos Sur | Philippines | 17.3833333 | 120.4833333 | 45 | 47927 |
| Malammin | city | Province of Ilocos Sur | Philippines | 17.75 | 120.4666667 | 187 | 52649 |
| Malammin Sur | city | Province of Ilocos Sur | Philippines | 17.75 | 120.4666667 | 187 | 52649 |
| Malaya | city | Province of Ilocos Sur | Philippines | 16.9822222 | 120.7172222 | 1505 | 6660 |
| Malideg | city | Province of Ilocos Sur | Philippines | 17.1586111 | 120.68 | 1259 | 3669 |
| Malingeb | city | Province of Ilocos Sur | Philippines | 17.6166667 | 120.4166667 | 16 | 72043 |
| Mamarsang | city | Province of Ilocos Sur | Philippines | 16.9111111 | 120.5744444 | 1443 | 11375 |
| Mambog | city | Province of Ilocos Sur | Philippines | 17.0833333 | 120.45 | 62 | 25396 |
| Mambog | city | Province of Ilocos Sur | Philippines | 17.3 | 120.45 | 65 | 24405 |
| Mambog | city | Province of Ilocos Sur | Philippines | 17.3508333 | 120.4883333 | 62 | 40757 |
| Mambug | city | Province of Ilocos Sur | Philippines | 17.3 | 120.45 | 65 | 24405 |
| Mambug | city | Province of Ilocos Sur | Philippines | 17.3508333 | 120.4883333 | 62 | 40757 |
| Mambug Norte | city | Province of Ilocos Sur | Philippines | 17.35 | 120.4833333 | 101 | 40757 |
| Mambug Sur | city | Province of Ilocos Sur | Philippines | 17.3508333 | 120.4883333 | 62 | 40757 |
| Man-atong | city | Province of Ilocos Sur | Philippines | 16.9530556 | 120.6188889 | 1938 | 6221 |
| Manabac | city | Province of Ilocos Sur | Philippines | 17.3333333 | 120.5 | 55 | 25605 |
| Manaboc | city | Province of Ilocos Sur | Philippines | 17.3333333 | 120.5 | 55 | 25605 |
| Manabuc | city | Province of Ilocos Sur | Philippines | 17.3333333 | 120.5 | 55 | 25605 |
| Manangat | city | Province of Ilocos Sur | Philippines | 17.5333333 | 120.3666667 | 3 | 44767 |
| Mananget | city | Province of Ilocos Sur | Philippines | 17.5333333 | 120.3666667 | 3 | 44767 |
| Manayon | city | Province of Ilocos Sur | Philippines | 17.15 | 120.45 | 170 | 40802 |
| Manga | city | Province of Ilocos Sur | Philippines | 17.2 | 120.55 | 984 | 16561 |
| Mantanas | city | Province of Ilocos Sur | Philippines | 17.0833333 | 120.45 | 62 | 25396 |
| Manueva | city | Province of Ilocos Sur | Philippines | 17.5166667 | 120.45 | 702 | 58129 |
| Manzante | city | Province of Ilocos Sur | Philippines | 17.7 | 120.4 | 19 | 29976 |
| Mapacac | city | Province of Ilocos Sur | Philippines | 16.9666667 | 120.6666667 | 3936 | 6374 |
| Mapalina | city | Province of Ilocos Sur | Philippines | 17.0166667 | 120.55 | 1906 | 9248 |
| Mapan | city | Province of Ilocos Sur | Philippines | 17.7333333 | 120.4666667 | 111 | 52649 |
| Mapanit | city | Province of Ilocos Sur | Philippines | 17.3333333 | 120.4833333 | 226 | 32306 |
| Maradudon | city | Province of Ilocos Sur | Philippines | 17.8 | 120.4833333 | 82 | 42855 |
| Maratudo | city | Province of Ilocos Sur | Philippines | 17.6847222 | 120.49 | 508 | 47352 |
| Margaay | city | Province of Ilocos Sur | Philippines | 17.4333333 | 120.4666667 | 82 | 47768 |
| Margaay | city | Province of Ilocos Sur | Philippines | 17.4391667 | 120.4680556 | 82 | 47768 |
| Marmarsang | city | Province of Ilocos Sur | Philippines | 16.9333333 | 120.5666667 | 2726 | 12633 |
| Marozo | city | Province of Ilocos Sur | Philippines | 17.4783333 | 120.5325 | 265 | 30562 |
| Masadag | city | Province of Ilocos Sur | Philippines | 17.8666667 | 120.5 | 141 | 31190 |
| Masingal | city | Province of Ilocos Sur | Philippines | 17.685 | 120.4244444 | 75 | 46641 |
| Masiosioay | city | Province of Ilocos Sur | Philippines | 17.25 | 120.6333333 | 1414 | 5205 |
| Maspiil | city | Province of Ilocos Sur | Philippines | 17.0166667 | 120.7333333 | 1486 | 5338 |
| Matanobong | city | Province of Ilocos Sur | Philippines | 17.3 | 120.4333333 | 164 | 24405 |
| Matanobong | city | Province of Ilocos Sur | Philippines | 17.1833333 | 120.4666667 | 95 | 49346 |
| Matanubong | city | Province of Ilocos Sur | Philippines | 17.1833333 | 120.4666667 | 95 | 49346 |
| Matbo | city | Province of Ilocos Sur | Philippines | 17.1166667 | 120.6166667 | 1794 | 7122 |
| Matibuay | city | Province of Ilocos Sur | Philippines | 17.2166667 | 120.6833333 | 1312 | 4256 |
| Matibuei | city | Province of Ilocos Sur | Philippines | 17.2166667 | 120.6833333 | 1312 | 4256 |
| Matibuey | city | Province of Ilocos Sur | Philippines | 17.2166667 | 120.6833333 | 1312 | 4256 |
| Matocbo | city | Province of Ilocos Sur | Philippines | 16.95 | 120.6666667 | 5620 | 6856 |
| Matue | city | Province of Ilocos Sur | Philippines | 17.1333333 | 120.6 | 820 | 7653 |
| Maupong | city | Province of Ilocos Sur | Philippines | 17.0166667 | 120.7333333 | 1486 | 5338 |
| Maynganay Norte | city | Province of Ilocos Sur | Philippines | 17.3833333 | 120.4833333 | 45 | 47927 |
| Maynganay Sur | city | Province of Ilocos Sur | Philippines | 17.3833333 | 120.4833333 | 45 | 47927 |
| McKinley | city | Province of Ilocos Sur | Philippines | 17.2166667 | 120.5 | 82 | 25542 |
| Mindoro | city | Province of Ilocos Sur | Philippines | 17.5583333 | 120.3519444 | 16 | 62243 |
| Mira | city | Province of Ilocos Sur | Philippines | 17.5833333 | 120.3833333 | 16 | 92225 |
| Mision | city | Province of Ilocos Sur | Philippines | 17.4333333 | 120.5166667 | 124 | 45796 |
| Mission | city | Province of Ilocos Sur | Philippines | 17.4333333 | 120.5166667 | 124 | 45796 |
| Montero | city | Province of Ilocos Sur | Philippines | 17.2333333 | 120.4833333 | 85 | 40323 |
| Morozo | city | Province of Ilocos Sur | Philippines | 17.4783333 | 120.5325 | 265 | 30562 |
| Muraya | city | Province of Ilocos Sur | Philippines | 17.7333333 | 120.4666667 | 111 | 52649 |
| Muruya | city | Province of Ilocos Sur | Philippines | 17.7333333 | 120.4666667 | 111 | 52649 |
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