San Guillermo comprises 26 barangays with an estimated population of 22,059. 26 of its barangays (100%) are connectivity dead zones with no recorded cell tower from either the national registry or crowdsourced data.
| Barangay | Population | Towers | Coverage |
|---|---|---|---|
| Anonang | 1,267 | 0 | Dead zone: no towers from any source |
| Aringay | 234 | 0 | Dead zone: no towers from any source |
| Burgos | 1,705 | 0 | Dead zone: no towers from any source |
| Calaoagan | 270 | 0 | Dead zone: no towers from any source |
| Centro 1 (Pob.) | 2,644 | 0 | Dead zone: no towers from any source |
| Centro 2 (Pob.) | 1,924 | 0 | Dead zone: no towers from any source |
| Colorado | 974 | 0 | Dead zone: no towers from any source |
| Dietban | 1,214 | 0 | Dead zone: no towers from any source |
| Dingading | 984 | 0 | Dead zone: no towers from any source |
| Dipacamo | 987 | 0 | Dead zone: no towers from any source |
| Estrella | 945 | 0 | Dead zone: no towers from any source |
| Guam | 1,083 | 0 | Dead zone: no towers from any source |
| Nakar | 586 | 0 | Dead zone: no towers from any source |
| Palawan | 473 | 0 | Dead zone: no towers from any source |
| Progreso | 634 | 0 | Dead zone: no towers from any source |
| Rizal | 1,438 | 0 | Dead zone: no towers from any source |
| San Francisco Norte | 895 | 0 | Dead zone: no towers from any source |
| San Francisco Sur | 423 | 0 | Dead zone: no towers from any source |
| San Mariano Norte | 341 | 0 | Dead zone: no towers from any source |
| San Mariano Sur | 744 | 0 | Dead zone: no towers from any source |
| San Rafael | 91 | 0 | Dead zone: no towers from any source |
| Sinalugan | 746 | 0 | Dead zone: no towers from any source |
| Villa Remedios | 219 | 0 | Dead zone: no towers from any source |
| Villa Rose | 264 | 0 | Dead zone: no towers from any source |
| Villa Sanchez | 734 | 0 | Dead zone: no towers from any source |
| Villa Teresita | 240 | 0 | Dead zone: no towers from any source |