| Merthyr Tudful to Carmona | 992.49 mi (1,597.26 km) |
| Merthyr Tudful to Cartagena | 984.11 mi (1,583.77 km) |
| Merthyr Tudful to Cartama | 1,040.39 mi (1,674.35 km) |
| Merthyr Tudful to Cartaya | 1,015.85 mi (1,634.85 km) |
| Merthyr Tudful to Caspe | 743.17 mi (1,196.01 km) |
| Merthyr Tudful to Cassa de la Selva | 741.57 mi (1,193.43 km) |
| Merthyr Tudful to Castalla | 917.67 mi (1,476.85 km) |
| Merthyr Tudful to Castellbisbal | 753.06 mi (1,211.93 km) |
| Merthyr Tudful to Castelldefels | 765.93 mi (1,232.64 km) |
| Merthyr Tudful to Castello de Ampurias | 721.75 mi (1,161.54 km) |
| Merthyr Tudful to Castellon de la Plana | 828.08 mi (1,332.67 km) |
| Merthyr Tudful to Castilleja de la Cuesta | 1,000.66 mi (1,610.41 km) |
| Merthyr Tudful to Catarroja | 864.48 mi (1,391.24 km) |
| Merthyr Tudful to Catral | 946.77 mi (1,523.69 km) |
| Merthyr Tudful to Caudete | 908.23 mi (1,461.65 km) |
