| Difficult Run to Mauldin (South Carolina) | 394.98 mi (635.67 km) |
| Difficult Run to Maumee (Ohio) | 380.62 mi (612.55 km) |
| Difficult Run to Maumelle (Arkansas) | 876.49 mi (1,410.58 km) |
| Difficult Run to Mayagüez (Puerto Rico) | 1,556.09 mi (2,504.29 km) |
| Difficult Run to Mayfield Heights (Ohio) | 282.10 mi (453.99 km) |
| Difficult Run to Mays Chapel (Maryland) | 52.37 mi (84.28 km) |
| Difficult Run to Maywood (California) | 2,276.05 mi (3,662.95 km) |
| Difficult Run to Maywood (Illinois) | 589.00 mi (947.90 km) |
| Difficult Run to McAlester (Oklahoma) | 1,052.27 mi (1,693.47 km) |
| Difficult Run to McAllen (Texas) | 1,493.31 mi (2,403.24 km) |
| Difficult Run to McCalla (Alabama) | 664.10 mi (1,068.77 km) |
| Difficult Run to McComb (Mississippi) | 909.88 mi (1,464.31 km) |
| Difficult Run to McDonough (Georgia) | 534.86 mi (860.77 km) |
| Difficult Run to McFarland (California) | 2,293.46 mi (3,690.96 km) |
| Difficult Run to McHenry (Illinois) | 620.65 mi (998.84 km) |
