| Harpenden to Cocentaina | 903.23 mi (1,453.61 km) |
| Harpenden to Coin | 1,068.71 mi (1,719.92 km) |
| Harpenden to Colindres | 599.28 mi (964.45 km) |
| Harpenden to Collado-Villalba | 792.00 mi (1,274.60 km) |
| Harpenden to Colmenar Viejo | 787.82 mi (1,267.88 km) |
| Harpenden to Colmenarejo | 797.00 mi (1,282.65 km) |
| Harpenden to Conil de la Frontera | 1,110.65 mi (1,787.41 km) |
| Harpenden to Consuegra | 867.81 mi (1,396.61 km) |
| Harpenden to Corbera de Llobregat | 726.64 mi (1,169.42 km) |
| Harpenden to Cordoba | 986.33 mi (1,587.34 km) |
| Harpenden to Coria del Rio | 1,041.86 mi (1,676.71 km) |
| Harpenden to Crevillente | 937.78 mi (1,509.21 km) |
| Harpenden to Cuarte de Huerva | 707.61 mi (1,138.79 km) |
| Harpenden to Cubellas | 739.13 mi (1,189.52 km) |
| Harpenden to Cuellar | 743.58 mi (1,196.68 km) |
