| Merthyr Tudful to Red Bank (New Jersey) | 3,341.39 mi (5,377.44 km) |
| Merthyr Tudful to Red Bank (Tennessee) | 4,040.29 mi (6,502.21 km) |
| Merthyr Tudful to Red Bluff (California) | 5,102.44 mi (8,211.58 km) |
| Merthyr Tudful to Red Hill (South Carolina) | 3,844.89 mi (6,187.76 km) |
| Merthyr Tudful to Red Oak (Texas) | 4,627.61 mi (7,447.42 km) |
| Merthyr Tudful to Red Wing (Minnesota) | 3,879.01 mi (6,242.67 km) |
| Merthyr Tudful to Redan (Georgia) | 4,060.13 mi (6,534.15 km) |
| Merthyr Tudful to Redding (California) | 5,083.52 mi (8,181.13 km) |
| Merthyr Tudful to Redland (Maryland) | 3,521.09 mi (5,666.65 km) |
| Merthyr Tudful to Redlands (California) | 5,288.63 mi (8,511.22 km) |
| Merthyr Tudful to Redmond (Oregon) | 4,839.95 mi (7,789.15 km) |
| Merthyr Tudful to Redmond (Washington) | 4,674.81 mi (7,523.39 km) |
| Merthyr Tudful to Redondo Beach (California) | 5,339.52 mi (8,593.13 km) |
| Merthyr Tudful to Redwood City (California) | 5,254.65 mi (8,456.54 km) |
| Merthyr Tudful to Reedley (California) | 5,219.27 mi (8,399.61 km) |
