| Difficult Run to Bound Brook (New Jersey) | 188.46 mi (303.30 km) |
| Difficult Run to Bountiful (Utah) | 1,823.19 mi (2,934.15 km) |
| Difficult Run to Bourbonnais (Illinois) | 578.51 mi (931.02 km) |
| Difficult Run to Bowie (Maryland) | 32.81 mi (52.80 km) |
| Difficult Run to Bowling Green (Kentucky) | 512.76 mi (825.21 km) |
| Difficult Run to Bowling Green (Ohio) | 374.15 mi (602.13 km) |
| Difficult Run to Box Elder (South Dakota) | 1,373.10 mi (2,209.79 km) |
| Difficult Run to Boynton Beach (Florida) | 869.45 mi (1,399.24 km) |
| Difficult Run to Bozeman (Montana) | 1,770.98 mi (2,850.12 km) |
| Difficult Run to Bradenton (Florida) | 844.00 mi (1,358.29 km) |
| Difficult Run to Bradfordville (Florida) | 694.29 mi (1,117.35 km) |
| Difficult Run to Bradley (Illinois) | 576.54 mi (927.86 km) |
| Difficult Run to Bradley Gardens (New Jersey) | 183.21 mi (294.85 km) |
| Difficult Run to Brainerd (Minnesota) | 996.48 mi (1,603.68 km) |
| Difficult Run to Brambleton (Virginia) | 11.34 mi (18.25 km) |
