| Watford to Clacton-on-Sea | 66.64 mi (107.25 km) |
| Watford to Clay Cross | 112.71 mi (181.39 km) |
| Watford to Clayton | 158.48 mi (255.05 km) |
| Watford to Clayton le Moors | 168.45 mi (271.10 km) |
| Watford to Cleckheaton | 153.38 mi (246.84 km) |
| Watford to Cleethorpes | 132.10 mi (212.59 km) |
| Watford to Clevedon | 106.68 mi (171.69 km) |
| Watford to Clifton | 92.40 mi (148.70 km) |
| Watford to Clifton | 162.76 mi (261.93 km) |
| Watford to Cliftonville | 79.56 mi (128.04 km) |
| Watford to Clitheroe | 174.36 mi (280.61 km) |
| Watford to Clydebank | 335.65 mi (540.18 km) |
| Watford to Coalville | 84.59 mi (136.13 km) |
| Watford to Coatbridge | 326.25 mi (525.05 km) |
| Watford to Cobham | 22.53 mi (36.26 km) |
