| Merthyr Tudful to Black Forest (Colorado) | 4,586.58 mi (7,381.39 km) |
| Merthyr Tudful to Blackfoot (Idaho) | 4,629.16 mi (7,449.92 km) |
| Merthyr Tudful to Blackhawk (California) | 5,226.96 mi (8,411.98 km) |
| Merthyr Tudful to Blacksburg (Virginia) | 3,741.88 mi (6,021.97 km) |
| Merthyr Tudful to Blackwells Mills (New Jersey) | 3,357.63 mi (5,403.58 km) |
| Merthyr Tudful to Blaine (Minnesota) | 3,874.02 mi (6,234.63 km) |
| Merthyr Tudful to Bloomingdale (Florida) | 4,269.32 mi (6,870.80 km) |
| Merthyr Tudful to Bloomingdale (Illinois) | 3,830.08 mi (6,163.93 km) |
| Merthyr Tudful to Bloomington (California) | 5,295.79 mi (8,522.75 km) |
| Merthyr Tudful to Bloomington (Illinois) | 3,932.28 mi (6,328.39 km) |
| Merthyr Tudful to Bloomington (Indiana) | 3,897.82 mi (6,272.94 km) |
| Merthyr Tudful to Bloomington (Minnesota) | 3,893.55 mi (6,266.07 km) |
| Merthyr Tudful to Bloomsburg (Pennsylvania) | 3,410.96 mi (5,489.41 km) |
| Merthyr Tudful to Blue Ash (Ohio) | 3,808.82 mi (6,129.70 km) |
| Merthyr Tudful to Blue Island (Illinois) | 3,827.71 mi (6,160.10 km) |
