San Agustin comprises 13 barangays with an estimated population of 15,077. 8 of its barangays (62%) are connectivity dead zones with no recorded cell tower from either the national registry or crowdsourced data.
| Barangay | Population | Towers | Coverage |
|---|---|---|---|
| Bretania | 1,302 | 4 | Crowdsourced signal only (no registered tower) |
| Buatong | 2,313 | 0 | Dead zone: no towers from any source |
| Buhisan | 895 | 0 | Dead zone: no towers from any source |
| Gata | 1,097 | 7 | Crowdsourced signal only (no registered tower) |
| Hornasan | 2,119 | 1 | Crowdsourced signal only (no registered tower) |
| Janipaan | 747 | 0 | Dead zone: no towers from any source |
| Kauswagan | 1,159 | 0 | Dead zone: no towers from any source |
| Oteiza | 1,695 | 1 | Crowdsourced signal only (no registered tower) |
| Poblacion | 222 | 0 | Dead zone: no towers from any source |
| Pong-on | 414 | 0 | Dead zone: no towers from any source |
| Pongtod | 1,168 | 0 | Dead zone: no towers from any source |
| Salvacion | 1,205 | 1 | Crowdsourced signal only (no registered tower) |
| Santo Niño | 741 | 0 | Dead zone: no towers from any source |