| Difficult Run to Firestone (Colorado) | 1,467.61 mi (2,361.90 km) |
| Difficult Run to Fish Hawk (Florida) | 813.21 mi (1,308.73 km) |
| Difficult Run to Fishers (Indiana) | 465.54 mi (749.21 km) |
| Difficult Run to Fitchburg (Massachusetts) | 385.62 mi (620.60 km) |
| Difficult Run to Fitchburg (Wisconsin) | 689.80 mi (1,110.12 km) |
| Difficult Run to Five Corners (Washington) | 2,326.40 mi (3,743.97 km) |
| Difficult Run to Five Forks (South Carolina) | 390.81 mi (628.95 km) |
| Difficult Run to Flagstaff (Arizona) | 1,896.15 mi (3,051.56 km) |
| Difficult Run to Flat Rock (Michigan) | 381.55 mi (614.04 km) |
| Difficult Run to Fleming Island (Florida) | 656.82 mi (1,057.04 km) |
| Difficult Run to Flint (Michigan) | 436.47 mi (702.43 km) |
| Difficult Run to Floral Park (New York) | 230.71 mi (371.29 km) |
| Difficult Run to Florence (Alabama) | 635.43 mi (1,022.63 km) |
| Difficult Run to Florence (Arizona) | 1,935.63 mi (3,115.10 km) |
| Difficult Run to Florence (Kentucky) | 392.22 mi (631.22 km) |
