La Castellana comprises 13 barangays with an estimated population of 75,620. 2 of its barangays (15%) are connectivity dead zones with no recorded cell tower from either the national registry or crowdsourced data.
| Barangay | Population | Towers | Coverage |
|---|---|---|---|
| Biaknabato | 6,455 | 2 | Crowdsourced signal only (no registered tower) |
| Cabacungan | 8,033 | 3 | Crowdsourced signal only (no registered tower) |
| Cabagnaan | 5,766 | 2 | Crowdsourced signal only (no registered tower) |
| Camandag | 4,032 | 5 | Crowdsourced signal only (no registered tower) |
| Lalagsan | 2,365 | 3 | Crowdsourced signal only (no registered tower) |
| Manghanoy | 6,165 | 3 | Crowdsourced signal only (no registered tower) |
| Mansalanao | 2,692 | 1 | Crowdsourced signal only (no registered tower) |
| Masulog | 3,056 | 3 | Crowdsourced signal only (no registered tower) |
| Nato | 4,737 | 1 | Crowdsourced signal only (no registered tower) |
| Puso | 1,756 | 0 | Dead zone: no towers from any source |
| Robles (Pob.) | 18,942 | 16 | Crowdsourced signal only (no registered tower) |
| Sag-Ang | 10,469 | 4 | Crowdsourced signal only (no registered tower) |
| Talaptap | 1,152 | 0 | Dead zone: no towers from any source |