| Difficult Run to Camarillo (California) | 2,315.62 mi (3,726.63 km) |
| Difficult Run to Camas (Washington) | 2,320.01 mi (3,733.69 km) |
| Difficult Run to Cambridge (Maryland) | 72.52 mi (116.71 km) |
| Difficult Run to Cambridge (Massachusetts) | 405.12 mi (651.97 km) |
| Difficult Run to Camden (Arkansas) | 937.55 mi (1,508.85 km) |
| Difficult Run to Camden (New Jersey) | 139.28 mi (224.15 km) |
| Difficult Run to Cameron Park (California) | 2,327.31 mi (3,745.45 km) |
| Difficult Run to Camp Pendleton South (California) | 2,252.23 mi (3,624.61 km) |
| Difficult Run to Camp Springs (Maryland) | 23.93 mi (38.51 km) |
| Difficult Run to Camp Verde (Arizona) | 1,922.49 mi (3,093.94 km) |
| Difficult Run to Campbell (California) | 2,403.90 mi (3,868.70 km) |
| Difficult Run to Campbellsville (Kentucky) | 447.99 mi (720.97 km) |
| Difficult Run to Campton Hills (Illinois) | 618.58 mi (995.51 km) |
| Difficult Run to Canby (Oregon) | 2,334.47 mi (3,756.97 km) |
| Difficult Run to Candelaria (Puerto Rico) | 1,565.72 mi (2,519.79 km) |
