| Difficult Run to Cockermouth | 3,487.24 mi (5,612.17 km) |
| Difficult Run to Colchester | 3,710.71 mi (5,971.81 km) |
| Difficult Run to Coleford | 3,569.94 mi (5,745.26 km) |
| Difficult Run to Colne | 3,547.79 mi (5,709.61 km) |
| Difficult Run to Colwyn Bay | 3,497.74 mi (5,629.07 km) |
| Difficult Run to Congleton | 3,559.21 mi (5,727.99 km) |
| Difficult Run to Conisbrough | 3,592.29 mi (5,781.23 km) |
| Difficult Run to Connahs Quay | 3,524.69 mi (5,672.44 km) |
| Difficult Run to Consett | 3,543.07 mi (5,702.03 km) |
| Difficult Run to Conwy | 3,492.73 mi (5,621.00 km) |
| Difficult Run to Cookstown | 3,355.68 mi (5,400.44 km) |
| Difficult Run to Corby | 3,633.26 mi (5,847.17 km) |
| Difficult Run to Corfe Mullen | 3,615.75 mi (5,818.98 km) |
| Difficult Run to Corsham | 3,594.88 mi (5,785.40 km) |
| Difficult Run to Coseley | 3,576.48 mi (5,755.78 km) |
