| Difficult Run to Buena Park (California) | 2,269.44 mi (3,652.31 km) |
| Difficult Run to Buenaventura Lakes (Florida) | 765.39 mi (1,231.77 km) |
| Difficult Run to Buffalo (Minnesota) | 949.63 mi (1,528.28 km) |
| Difficult Run to Buffalo (New York) | 287.28 mi (462.34 km) |
| Difficult Run to Buffalo Grove (Illinois) | 600.79 mi (966.88 km) |
| Difficult Run to Buford (Georgia) | 495.00 mi (796.63 km) |
| Difficult Run to Bull Run (Virginia) | 12.54 mi (20.19 km) |
| Difficult Run to Bullhead City (Arizona) | 2,054.62 mi (3,306.59 km) |
| Difficult Run to Burbank (California) | 2,278.51 mi (3,666.91 km) |
| Difficult Run to Burbank (Illinois) | 582.59 mi (937.59 km) |
| Difficult Run to Burien (Washington) | 2,307.98 mi (3,714.34 km) |
| Difficult Run to Burkburnett (Texas) | 1,221.84 mi (1,966.36 km) |
| Difficult Run to Burke (Virginia) | 9.70 mi (15.61 km) |
| Difficult Run to Burke Centre (Virginia) | 8.10 mi (13.03 km) |
| Difficult Run to Burleson (Texas) | 1,201.80 mi (1,934.11 km) |
