| Difficult Run to Cadiz | 3,783.98 mi (6,089.73 km) |
| Difficult Run to Calafell | 4,024.67 mi (6,477.09 km) |
| Difficult Run to Calahorra | 3,827.39 mi (6,159.58 km) |
| Difficult Run to Calasparra | 3,959.44 mi (6,372.11 km) |
| Difficult Run to Calatayud | 3,869.94 mi (6,228.06 km) |
| Difficult Run to Caldas de Montbuy | 4,039.36 mi (6,500.72 km) |
| Difficult Run to Caldas de Reyes | 3,504.53 mi (5,640.00 km) |
| Difficult Run to Calella | 4,062.86 mi (6,538.54 km) |
| Difficult Run to Callosa de Segura | 4,002.63 mi (6,441.61 km) |
| Difficult Run to Calpe | 4,031.01 mi (6,487.29 km) |
| Difficult Run to Calvia | 4,119.50 mi (6,629.70 km) |
| Difficult Run to Camas | 3,771.40 mi (6,069.48 km) |
| Difficult Run to Cambados | 3,499.31 mi (5,631.59 km) |
| Difficult Run to Cambre | 3,502.71 mi (5,637.06 km) |
| Difficult Run to Cambrils | 4,004.73 mi (6,444.99 km) |
