San Marcelino comprises 18 barangays with an estimated population of 44,848. 10 of its barangays (56%) are connectivity dead zones with no recorded cell tower from either the national registry or crowdsourced data.
| Barangay | Population | Towers | Coverage |
|---|---|---|---|
| Aglao | 3,981 | 0 | Dead zone: no towers from any source |
| Buhawen | 7,202 | 0 | Dead zone: no towers from any source |
| Burgos (Pob.) | 3,129 | 0 | Dead zone: no towers from any source |
| Central (Pob.) | 313 | 0 | Dead zone: no towers from any source |
| Consuelo Norte | 5,833 | 2 | Crowdsourced signal only (no registered tower) |
| Consuelo Sur (Pob.) | 1,888 | 1 | Crowdsourced signal only (no registered tower) |
| La Paz (Pob.) | 858 | 5 | Crowdsourced signal only (no registered tower) |
| Laoag | 1,668 | 0 | Dead zone: no towers from any source |
| Linasin | 2,465 | 3 | Crowdsourced signal only (no registered tower) |
| Linusungan | 2,254 | 2 | Crowdsourced signal only (no registered tower) |
| Lucero (Pob.) | 1,522 | 0 | Dead zone: no towers from any source |
| Nagbunga | 2,498 | 2 | Crowdsourced signal only (no registered tower) |
| Rabanes | 2,171 | 0 | Dead zone: no towers from any source |
| Rizal (Pob.) | 282 | 0 | Dead zone: no towers from any source |
| San Guillermo (Pob.) | 530 | 2 | Crowdsourced signal only (no registered tower) |
| San Isidro (Pob.) | 2,800 | 3 | Crowdsourced signal only (no registered tower) |
| San Rafael | 1,276 | 0 | Dead zone: no towers from any source |
| Santa Fe | 4,178 | 0 | Dead zone: no towers from any source |