L1 — 20 codes dans 20 localités (Canada).
| Code postal | Localité / Quartier | Zone administrative | Coordonnées |
|---|---|---|---|
| Port Hope | Ontario | 44.0168, -78.3995 | |
| Bowmanville East | Bowmanville · Ontario | 43.9235, -78.5457 | |
| Bowmanville West | Bowmanville · Ontario | 43.9714, -78.7095 | |
| Courtice | Ontario | 43.8969, -78.7683 | |
| Oshawa Central | Oshawa · Ontario | 43.9233, -78.8684 | |
| Oshawa Southeast | Oshawa · Ontario | 43.9721, -78.8837 | |
| Oshawa Southwest | Oshawa · Ontario | 43.8852, -78.8771 | |
| Oshawa East | Oshawa · Ontario | 43.9251, -78.8287 | |
| Oshawa North | Oshawa · Ontario | 43.9581, -78.8972 | |
| Whitby North | Whitby · Ontario | 43.9566, -78.9779 | |
| Whitby Southeast | Whitby · Ontario | 43.8721, -78.9273 | |
| Whitby Southwest | Whitby · Ontario | 43.8866, -78.975 | |
| Whitby Central | Whitby · Ontario | 43.9215, -78.9412 | |
| Ajax Southwest | Ajax · Ontario | 43.8404, -79.0251 | |
| Ajax Northwest | Ajax · Ontario | 43.8843, -79.0534 | |
| Pickering Southwest | Pickering · Ontario | 43.8605, -79.1618 | |
| Pickering South | Pickering · Ontario | 43.8197, -79.0803 | |
| Pickering Central | Pickering · Ontario | 43.8558, -79.0972 | |
| Pickering North | Pickering · Ontario | 43.9555, -79.1194 | |
| Ajax East | Ajax · Ontario | 43.8773, -79.0055 |