| Code | Name | Region |
|---|---|---|
| GBCMA | Cefn-mawr | WRX |
| GBCEI | Ceinewydd (new Quay) | CGN |
| GBCEL | Cellardyke | FIF |
| GBCEB | Cemaes Bay | AGY |
| GBCNM | Central Mainland (shetland) | ZET |
| GBRRI | Cerrigdrudion | CWY |
| GBCDD | Chadderton | OLD |
| GBADS | Chaddesden | DER |
| GBCH7 | Chadlington | OXF |
| GBCDZ | Chadwell | LEC |
| GBCDW | Chadwell Heath | RDB |
| GBCDE | Chadwell Saint Mary | ESS |
| GBCJY | Chailey | ESX |
| GBCHQ | Chale | IOW |
| GBCSG | Chalfont Saint Giles | BKM |
| GBCSP | Chalfont Saint Peter | BKM |
| GBCCY | Castlecary | FAL |
| GBCDN | Castledawson | MFT |
| GBZST | Castlederg | STB |
| GBCTF | Castleford | WKF |
| GBCAS | Castleton | DBY |
| GBCTS | Castleton | RCH |
| GBCSW | Castletown | DOR |
| GBCTN | Castletown | HLD |
| GBCWX | Castlewellan | DOW |
| GBOTM | Catcott | SOM |
| GBCTR | Caterham | SRY |
| GBCTL | Catfield | NFK |
| GBFT8 | Catford | LEW |
| GBCAT | Catrine | EAY |
| GBCCR | Catterick | NYK |
| GBCCE | Catterline | ABD |
| GBCVM | Cavenham | SFK |
| GBCVF | Caversfield | OXF |
| GBCVR | Caversham | RDG |
| GBCNX | Cawsand | CON |
| GBRRN | Carron | MRY |
| GBCR9 | Carrutherstown | DGY |
| GBCFF | Carryduff | ARD |
| GBCSI | Carsaig | AGB |
| GBCET | Carsethorn | |
| GBCTO | Carshalton | STN |
| GBCA9 | Carstairs | SLK |
| GBZAM | Carterton | OXF |
| GBATW | Carthew | CON |
| GBTML | Cartmel | CMA |
| GBCCB | Cascob | POW |
| GBCGO | Cassington | OXF |
| GBCSB | Castle Bromwich | BIR |
| GBCLB | Castle Bytham | LIN |