Cagayan has 820 barangays across 29 municipalities. 549 barangays (67%) are connectivity dead zones.
| Municipality | Barangays | Dead zones |
|---|---|---|
| Abulug | 20 | 11 (55%) |
| Alcala | 25 | 17 (68%) |
| Allacapan | 27 | 23 (85%) |
| Amulung | 47 | 34 (72%) |
| Aparri | 42 | 27 (64%) |
| Baggao | 48 | 34 (71%) |
| Ballesteros | 19 | 13 (68%) |
| Buguey | 30 | 24 (80%) |
| Calayan | 12 | 12 (100%) |
| Camalaniugan | 28 | 21 (75%) |
| Claveria | 41 | 30 (73%) |
| Enrile | 22 | 13 (59%) |
| Gattaran | 50 | 30 (60%) |
| Gonzaga | 25 | 12 (48%) |
| Iguig | 23 | 8 (35%) |
| Lal-lo | 35 | 19 (54%) |
| Lasam | 30 | 26 (87%) |
| Pamplona | 18 | 14 (78%) |
| Peñablanca | 24 | 17 (71%) |
| Piat | 18 | 13 (72%) |
| Rizal | 29 | 29 (100%) |
| Sanchez-Mira | 18 | 14 (78%) |
| Santa Ana | 16 | 9 (56%) |
| Santa Praxedes | 10 | 9 (90%) |
| Santa Teresita | 13 | 7 (54%) |
| Santo Niño (Faire) | 31 | 30 (97%) |
| Solana | 38 | 24 (63%) |
| Tuao | 32 | 27 (84%) |
| Tuguegarao City (Capital) | 49 | 2 (4%) |