| Locality | Postal Code |
|---|---|
| Postal/ZIP Codes in Collier Row | RM5 |
| Postal/ZIP Codes in Elm Park | RM12 5NR |
| Postal/ZIP Codes in Gidea Park | RM2 |
| Postal/ZIP Codes in Harold Hill | RM3 |
| Postal/ZIP Codes in Harold Wood | RM3 |
| Postal/ZIP Codes in Havering-Atte-Bower | RM4 |
| Postal/ZIP Codes in Heath Park | RM2 5XL |
| Postal/ZIP Codes in Hornchurch | RM11, RM12 |
| Postal/ZIP Codes in Mawneys | RM7 |
| Postal/ZIP Codes in Noak Hill | RM3, RM4 |
| Postal/ZIP Codes in North Ockendon | RM14 |
| Postal/ZIP Codes in Rainham | RM13 |
| Postal/ZIP Codes in Romford | RM1, RM2, RM3, RM5, RM7 |
| Postal/ZIP Codes in Upminster | RM14 |
| Postal/ZIP Codes in Wennington | RM13 |