| Locality | Post Code |
|---|---|
| Church Kelloe | DH6 4PT |
| Cleatlam | DL2 |
| Close House | DL14 |
| Cockfield | DL13 |
| Cold Hesledon | SR7 |
| Consett | DH8 |
| Copley | DL13 |
| Cornriggs | DL13 |
| Cornsay | DH7 |
| Cornsay Colliery | DH7 |
| Coronation | DL14 |
| Cotherstone | DL12 |
| Coundon | DL14 |
| Coundon Gate | DL14 |
| Coundon Grange | DL14 |
| Cowshill | DL13 |
| Coxhoe | DH6 |
| Craghead | DH9 |
| Craghead Colliery Industrial Estate | DH9 6HB |
| Crook | DL15 |
| Crookhall | DH8 |
| Crossgate Moor | DH1 |
| Croxdale | DH6 |
| Daddry Shield | DL13 |
| Dalton-Le-Dale | SR7 |
| Davy Lamp | DH6 4PQ |