| Difficult Run to Arcata (California) | 2,451.67 mi (3,945.58 km) |
| Difficult Run to Archdale (North Carolina) | 251.91 mi (405.41 km) |
| Difficult Run to Arden-Arcade (California) | 2,349.32 mi (3,780.86 km) |
| Difficult Run to Ardmore (Oklahoma) | 1,142.34 mi (1,838.41 km) |
| Difficult Run to Ardmore (Pennsylvania) | 133.35 mi (214.61 km) |
| Difficult Run to Arecibo (Puerto Rico) | 1,549.78 mi (2,494.13 km) |
| Difficult Run to Arkadelphia (Arkansas) | 932.01 mi (1,499.93 km) |
| Difficult Run to Arkansas City (Kansas) | 1,077.61 mi (1,734.24 km) |
| Difficult Run to Arlington (Tennessee) | 723.54 mi (1,164.42 km) |
| Difficult Run to Arlington (Texas) | 1,185.21 mi (1,907.41 km) |
| Difficult Run to Arlington (Virginia) | 13.32 mi (21.44 km) |
| Difficult Run to Arlington (Washington) | 2,297.79 mi (3,697.93 km) |
| Difficult Run to Arlington Heights (Illinois) | 600.26 mi (966.02 km) |
| Difficult Run to Arnold (Maryland) | 46.69 mi (75.13 km) |
| Difficult Run to Arnold (Missouri) | 702.90 mi (1,131.21 km) |
