| Difficult Run to Mountain Brook (Alabama) | 643.05 mi (1,034.89 km) |
| Difficult Run to Mountain Home (Arkansas) | 840.78 mi (1,353.11 km) |
| Difficult Run to Mountain Home (Idaho) | 2,002.75 mi (3,223.12 km) |
| Difficult Run to Mountain House (California) | 2,372.93 mi (3,818.87 km) |
| Difficult Run to Mountain Park (Georgia) | 513.98 mi (827.16 km) |
| Difficult Run to Mountain Top (Pennsylvania) | 172.17 mi (277.08 km) |
| Difficult Run to Mountain View (California) | 2,408.14 mi (3,875.53 km) |
| Difficult Run to Mountlake Terrace (Washington) | 2,305.86 mi (3,710.92 km) |
| Difficult Run to Mukilteo (Washington) | 2,305.47 mi (3,710.29 km) |
| Difficult Run to Muncie (Indiana) | 437.86 mi (704.66 km) |
| Difficult Run to Mundelein (Illinois) | 605.41 mi (974.32 km) |
| Difficult Run to Munhall (Pennsylvania) | 170.51 mi (274.41 km) |
| Difficult Run to Munster (Indiana) | 565.71 mi (910.43 km) |
| Difficult Run to Murfreesboro (Tennessee) | 540.25 mi (869.45 km) |
| Difficult Run to Murphy (Texas) | 1,148.66 mi (1,848.59 km) |
