| Difficult Run to Merrick (New York) | 234.91 mi (378.05 km) |
| Difficult Run to Merrifield (Virginia) | 5.96 mi (9.58 km) |
| Difficult Run to Merrillville (Indiana) | 555.16 mi (893.44 km) |
| Difficult Run to Merritt Island (Florida) | 755.97 mi (1,216.61 km) |
| Difficult Run to Mesa (Arizona) | 1,942.91 mi (3,126.81 km) |
| Difficult Run to Mesquite (Nevada) | 1,998.53 mi (3,216.33 km) |
| Difficult Run to Mesquite (Texas) | 1,155.40 mi (1,859.44 km) |
| Difficult Run to Metairie (Louisiana) | 953.73 mi (1,534.87 km) |
| Difficult Run to Methuen Town (Massachusetts) | 416.70 mi (670.61 km) |
| Difficult Run to Metuchen (New Jersey) | 194.93 mi (313.71 km) |
| Difficult Run to Mexico (Missouri) | 778.90 mi (1,253.52 km) |
| Difficult Run to Miami (Florida) | 921.47 mi (1,482.96 km) |
| Difficult Run to Miami (Oklahoma) | 964.03 mi (1,551.45 km) |
| Difficult Run to Miami Beach (Florida) | 918.49 mi (1,478.16 km) |
| Difficult Run to Miami Gardens (Florida) | 910.97 mi (1,466.06 km) |
