| Difficult Run to Cordele (Georgia) | 600.47 mi (966.36 km) |
| Difficult Run to Corinth (Mississippi) | 673.99 mi (1,084.69 km) |
| Difficult Run to Corinth (Texas) | 1,168.75 mi (1,880.92 km) |
| Difficult Run to Cornelius (North Carolina) | 306.51 mi (493.28 km) |
| Difficult Run to Cornelius (Oregon) | 2,350.41 mi (3,782.62 km) |
| Difficult Run to Corning (New York) | 224.76 mi (361.71 km) |
| Difficult Run to Corona (California) | 2,245.75 mi (3,614.18 km) |
| Difficult Run to Coronado (California) | 2,254.47 mi (3,628.21 km) |
| Difficult Run to Corpus Christi (Texas) | 1,385.60 mi (2,229.91 km) |
| Difficult Run to Corsicana (Texas) | 1,171.22 mi (1,884.89 km) |
| Difficult Run to Cortland (New York) | 262.77 mi (422.89 km) |
| Difficult Run to Corvallis (Oregon) | 2,368.42 mi (3,811.60 km) |
| Difficult Run to Coshocton (Ohio) | 257.41 mi (414.26 km) |
| Difficult Run to Costa Mesa (California) | 2,269.26 mi (3,652.02 km) |
| Difficult Run to Coto de Caza (California) | 2,253.44 mi (3,626.56 km) |
