San Isidro comprises 19 barangays with an estimated population of 24,549. 19 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 |
|---|---|---|---|
| Banat-e | 2,650 | 0 | Dead zone: no towers from any source |
| Basud | 1,487 | 0 | Dead zone: no towers from any source |
| Bawod (Pob.) | 2,146 | 0 | Dead zone: no towers from any source |
| Biasong | 1,660 | 0 | Dead zone: no towers from any source |
| Bunacan | 447 | 0 | Dead zone: no towers from any source |
| Busay | 1,119 | 0 | Dead zone: no towers from any source |
| Cabungaan | 571 | 0 | Dead zone: no towers from any source |
| Capiñahan (Pob.) | 2,181 | 0 | Dead zone: no towers from any source |
| Crossing (Pob.) | 1,876 | 0 | Dead zone: no towers from any source |
| Daja-daku | 2,835 | 0 | Dead zone: no towers from any source |
| Daja-diot | 1,282 | 0 | Dead zone: no towers from any source |
| Hacienda Maria | 1,032 | 0 | Dead zone: no towers from any source |
| Linao | 827 | 0 | Dead zone: no towers from any source |
| Matungao | 341 | 0 | Dead zone: no towers from any source |
| Paril | 714 | 0 | Dead zone: no towers from any source |
| San Jose | 440 | 0 | Dead zone: no towers from any source |
| San Miguel | 921 | 0 | Dead zone: no towers from any source |
| Taglawigan | 1,672 | 0 | Dead zone: no towers from any source |
| Tinago | 348 | 0 | Dead zone: no towers from any source |