| All postal codes in Gampaha |
| Attanagalla, Gampaha |
| Biyagama, Gampaha |
| Divulapitiya, Gampaha |
| Dompe, Gampaha |
| Gampaha, Gampaha |
| Ja-Ela, Gampaha |
| Katana, Gampaha |
| Kelaniya, Gampaha |
| Mahara, Gampaha |
| Minuwangoda, Gampaha |
| Mirigama, Gampaha |
| Negombo, Gampaha |
| Wattala, Gampaha |