San Ildefonso comprises 36 barangays with an estimated population of 109,759. 12 of its barangays (33%) are connectivity dead zones with no recorded cell tower from either the national registry or crowdsourced data.
| Barangay | Population | Towers | Coverage |
|---|---|---|---|
| Akle | 10,606 | 9 | Crowdsourced signal only (no registered tower) |
| Alagao | 5,635 | 1 | Crowdsourced signal only (no registered tower) |
| Anyatam | 1,386 | 27 | Crowdsourced signal only (no registered tower) |
| Bagong Barrio | 2,275 | 0 | Dead zone: no towers from any source |
| Basuit | 6,548 | 0 | Dead zone: no towers from any source |
| Bubulong Malaki | 5,516 | 0 | Dead zone: no towers from any source |
| Bubulong Munti | 3,095 | 1 | Crowdsourced signal only (no registered tower) |
| Buhol na Mangga | 8,408 | 3 | Crowdsourced signal only (no registered tower) |
| Bulusukan | 2,964 | 0 | Dead zone: no towers from any source |
| Calasag | 446 | 1 | Crowdsourced signal only (no registered tower) |
| Calawitan | 769 | 1 | Crowdsourced signal only (no registered tower) |
| Casalat | 3,825 | 0 | Dead zone: no towers from any source |
| Gabihan | 6,491 | 5 | Crowdsourced signal only (no registered tower) |
| Garlang | 482 | 17 | Crowdsourced signal only (no registered tower) |
| Lapnit | 243 | 0 | Dead zone: no towers from any source |
| Maasim | 3,626 | 17 | Crowdsourced signal only (no registered tower) |
| Makapilapil | 535 | 10 | Crowdsourced signal only (no registered tower) |
| Malipampang | 2,810 | 12 | Crowdsourced signal only (no registered tower) |
| Mataas na Parang | 947 | 2 | Crowdsourced signal only (no registered tower) |
| Matimbubong | 378 | 20 | Crowdsourced signal only (no registered tower) |
| Nabaong Garlang | 545 | 2 | Crowdsourced signal only (no registered tower) |
| Palapala | 8,503 | 11 | Crowdsourced signal only (no registered tower) |
| Pasong Bangkal | 4,308 | 0 | Dead zone: no towers from any source |
| Pinaod | 1,131 | 2 | Crowdsourced signal only (no registered tower) |
| Poblacion | 349 | 8 | Crowdsourced signal only (no registered tower) |
| Pulong Tamo | 392 | 0 | Dead zone: no towers from any source |
| San Juan | 388 | 16 | Crowdsourced signal only (no registered tower) |
| Santa Catalina Bata | 219 | 2 | Crowdsourced signal only (no registered tower) |
| Santa Catalina Matanda | 2,542 | 2 | Crowdsourced signal only (no registered tower) |
| Sapang Dayap | 4,602 | 0 | Dead zone: no towers from any source |
| Sapang Putik | 3,984 | 2 | Crowdsourced signal only (no registered tower) |
| Sapang Putol | 389 | 13 | Crowdsourced signal only (no registered tower) |
| Sumandig | 7,535 | 0 | Dead zone: no towers from any source |
| Telepatio | 894 | 0 | Dead zone: no towers from any source |
| Umpucan | 3,852 | 1 | Crowdsourced signal only (no registered tower) |
| Upig | 3,141 | 0 | Dead zone: no towers from any source |