| Name | What | Region | Country | Lat | Long | Elev Ft. | Pop Est |
| Dacag | city | Province of Ilocos Sur | Philippines | 17.1666667 | 120.7 | 1515 | 3745 |
| Daclapan | city | Province of Ilocos Sur | Philippines | 17.8 | 120.4166667 | 32 | 37587 |
| Dadalaquiten | city | Province of Ilocos Sur | Philippines | 17.9022222 | 120.4483333 | 78 | 18992 |
| Dadalaquiter | city | Province of Ilocos Sur | Philippines | 17.9022222 | 120.4483333 | 78 | 18992 |
| Daddaay | city | Province of Ilocos Sur | Philippines | 16.8833333 | 120.5333333 | 551 | 24676 |
| Dagat | city | Province of Ilocos Sur | Philippines | 17.6333333 | 120.55 | 278 | 21374 |
| Dagmam | city | Province of Ilocos Sur | Philippines | 17.1166667 | 120.6666667 | 1217 | 3758 |
| Dagupan | city | Province of Ilocos Sur | Philippines | 17.1666667 | 120.4833333 | 68 | 49346 |
| Dain | city | Province of Ilocos Sur | Philippines | 17.044444 | 120.7219444 | 1312 | 3949 |
| Daing | city | Province of Ilocos Sur | Philippines | 17.044444 | 120.7219444 | 1312 | 3949 |
| Daklapan | city | Province of Ilocos Sur | Philippines | 17.8 | 120.4166667 | 32 | 37587 |
| Dalaoa | city | Province of Ilocos Sur | Philippines | 16.9008333 | 120.5213889 | 278 | 24676 |
| Dalawa | city | Province of Ilocos Sur | Philippines | 16.9008333 | 120.5213889 | 278 | 24676 |
| Daligan | city | Province of Ilocos Sur | Philippines | 17.0666667 | 120.5 | 370 | 29505 |
| Dalipey | city | Province of Ilocos Sur | Philippines | 16.7775 | 120.5991667 | 2860 | 4825 |
| Damacuag | city | Province of Ilocos Sur | Philippines | 17.1166667 | 120.45 | 45 | 35098 |
| Dammay | city | Province of Ilocos Sur | Philippines | 17.5333333 | 120.4 | 16 | 68022 |
| Dan-ar | city | Province of Ilocos Sur | Philippines | 17.2508333 | 120.4411111 | 59 | 31043 |
| Danac | city | Province of Ilocos Sur | Philippines | 16.8 | 120.55 | 1853 | 7720 |
| Danuman | city | Province of Ilocos Sur | Philippines | 17.3833333 | 120.4666667 | 39 | 47927 |
| Danuman West | city | Province of Ilocos Sur | Philippines | 17.3833333 | 120.4666667 | 39 | 47927 |
| Dapdappig | city | Province of Ilocos Sur | Philippines | 17.1333333 | 120.6 | 820 | 7653 |
| Daramangan | city | Province of Ilocos Sur | Philippines | 17.7833333 | 120.4666667 | 65 | 50916 |
| Daramuangan | city | Province of Ilocos Sur | Philippines | 17.7833333 | 120.4666667 | 65 | 50916 |
| Darao | city | Province of Ilocos Sur | Philippines | 17.7333333 | 120.45 | 82 | 48847 |
| Darapidap | city | Province of Ilocos Sur | Philippines | 17.2130556 | 120.4113889 | 22 | 17661 |
| Darat | city | Province of Ilocos Sur | Philippines | 17.9666667 | 120.4833333 | 72 | 15895 |
| Dardara | city | Province of Ilocos Sur | Philippines | 17.7833333 | 120.4166667 | 3 | 47112 |
| Dardarat | city | Province of Ilocos Sur | Philippines | 17.7783333 | 120.4252778 | 36 | 47112 |
| Dardarat | city | Province of Ilocos Sur | Philippines | 16.95 | 120.4333333 | 114 | 30053 |
| Dasay | city | Province of Ilocos Sur | Philippines | 17.4166667 | 120.5 | 91 | 45796 |
| Dayanki | city | Province of Ilocos Sur | Philippines | 17.3333333 | 120.4833333 | 226 | 32306 |
| Dayapan | city | Province of Ilocos Sur | Philippines | 16.9227778 | 120.7416667 | 1876 | 7285 |
| Dili | city | Province of Ilocos Sur | Philippines | 17.0333333 | 120.45 | 49 | 17210 |
| Dill | city | Province of Ilocos Sur | Philippines | 17.0333333 | 120.45 | 49 | 17210 |
| Dinalaoan | city | Province of Ilocos Sur | Philippines | 17.4333333 | 120.4833333 | 82 | 47768 |
| Dinaratan | city | Province of Ilocos Sur | Philippines | 17.1116667 | 120.5266667 | 656 | 38398 |
| Dinaraton | city | Province of Ilocos Sur | Philippines | 17.1116667 | 120.5266667 | 656 | 38398 |
| Dinwiddie | city | Province of Ilocos Sur | Philippines | 16.95 | 120.7166667 | 2952 | 7285 |
| Dinwide | city | Province of Ilocos Sur | Philippines | 16.95 | 120.7166667 | 2952 | 7285 |
| Dirdirig | city | Province of Ilocos Sur | Philippines | 17.3166667 | 120.5 | 72 | 25605 |
| Dugay-yat | city | Province of Ilocos Sur | Philippines | 17.8508333 | 120.4875 | 324 | 37427 |
| Dupay | city | Province of Ilocos Sur | Philippines | 16.85 | 120.6 | 984 | 3911 |
| Duquis | city | Province of Ilocos Sur | Philippines | 17.0333333 | 120.5833333 | 2358 | 9248 |
| Duyayat | city | Province of Ilocos Sur | Philippines | 17.8508333 | 120.4875 | 324 | 37427 |
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