| Difficult Run to Frederick (Maryland) | 36.94 mi (59.45 km) |
| Difficult Run to Fredericksburg (Texas) | 1,357.58 mi (2,184.82 km) |
| Difficult Run to Fredericksburg (Virginia) | 42.30 mi (68.08 km) |
| Difficult Run to Frederickson (Washington) | 2,310.01 mi (3,717.60 km) |
| Difficult Run to Freeport (Illinois) | 685.05 mi (1,102.48 km) |
| Difficult Run to Freeport (New York) | 233.48 mi (375.75 km) |
| Difficult Run to Freeport (Texas) | 1,237.20 mi (1,991.08 km) |
| Difficult Run to Fremont (California) | 2,400.65 mi (3,863.47 km) |
| Difficult Run to Fremont (Nebraska) | 1,023.44 mi (1,647.06 km) |
| Difficult Run to Fremont (Ohio) | 348.52 mi (560.89 km) |
| Difficult Run to French Valley (California) | 2,227.62 mi (3,585.01 km) |
| Difficult Run to Fresno (California) | 2,299.74 mi (3,701.07 km) |
| Difficult Run to Fresno (Texas) | 1,217.48 mi (1,959.34 km) |
| Difficult Run to Fridley (Minnesota) | 919.80 mi (1,480.28 km) |
| Difficult Run to Friendly (Maryland) | 22.81 mi (36.71 km) |
