| Difficult Run to Conyers (Georgia) | 517.48 mi (832.80 km) |
| Difficult Run to Cookeville (Tennessee) | 485.88 mi (781.96 km) |
| Difficult Run to Coolidge (Arizona) | 1,944.41 mi (3,129.23 km) |
| Difficult Run to Coon Rapids (Minnesota) | 924.44 mi (1,487.74 km) |
| Difficult Run to Cooper City (Florida) | 904.43 mi (1,455.55 km) |
| Difficult Run to Coos Bay (Oregon) | 2,426.91 mi (3,905.73 km) |
| Difficult Run to Copiague (New York) | 242.93 mi (390.96 km) |
| Difficult Run to Coppell (Texas) | 1,170.09 mi (1,883.07 km) |
| Difficult Run to Copperas Cove (Texas) | 1,278.20 mi (2,057.07 km) |
| Difficult Run to Coral Gables (Florida) | 927.59 mi (1,492.81 km) |
| Difficult Run to Coral Springs (Florida) | 888.91 mi (1,430.56 km) |
| Difficult Run to Coral Terrace (Florida) | 925.04 mi (1,488.71 km) |
| Difficult Run to Coralville (Iowa) | 774.35 mi (1,246.19 km) |
| Difficult Run to Coram (New York) | 267.67 mi (430.77 km) |
| Difficult Run to Corcoran (California) | 2,301.78 mi (3,704.36 km) |
