| Harpenden to Caldicot | 103.81 mi (167.06 km) |
| Harpenden to Calne | 75.57 mi (121.62 km) |
| Harpenden to Cam | 86.41 mi (139.06 km) |
| Harpenden to Camberley | 37.30 mi (60.03 km) |
| Harpenden to Camborne | 241.88 mi (389.27 km) |
| Harpenden to Cambridge | 33.47 mi (53.86 km) |
| Harpenden to Cambuslang | 317.14 mi (510.39 km) |
| Harpenden to Canford Cliffs | 103.02 mi (165.80 km) |
| Harpenden to Cannock | 93.05 mi (149.75 km) |
| Harpenden to Canterbury | 71.88 mi (115.68 km) |
| Harpenden to Carlisle | 237.70 mi (382.54 km) |
| Harpenden to Carlton Colville | 97.17 mi (156.39 km) |
| Harpenden to Carluke | 305.58 mi (491.78 km) |
| Harpenden to Carnoustie | 337.31 mi (542.85 km) |
| Harpenden to Carshalton | 32.24 mi (51.89 km) |
