| Harpenden to Carmona | 1,024.28 mi (1,648.42 km) |
| Harpenden to Cartagena | 982.81 mi (1,581.68 km) |
| Harpenden to Cartama | 1,064.50 mi (1,713.15 km) |
| Harpenden to Cartaya | 1,057.38 mi (1,701.69 km) |
| Harpenden to Caspe | 731.45 mi (1,177.16 km) |
| Harpenden to Cassa de la Selva | 702.52 mi (1,130.60 km) |
| Harpenden to Castalla | 913.60 mi (1,470.29 km) |
| Harpenden to Castellbisbal | 722.91 mi (1,163.41 km) |
| Harpenden to Castelldefels | 736.33 mi (1,185.01 km) |
| Harpenden to Castello de Ampurias | 679.71 mi (1,093.89 km) |
| Harpenden to Castellon de la Plana | 817.82 mi (1,316.15 km) |
| Harpenden to Castilleja de la Cuesta | 1,035.14 mi (1,665.90 km) |
| Harpenden to Catarroja | 857.78 mi (1,380.46 km) |
| Harpenden to Catral | 943.94 mi (1,519.12 km) |
| Harpenden to Caudete | 906.55 mi (1,458.94 km) |
