| Merthyr Tudful to Ridgeland (Mississippi) | 4,368.48 mi (7,030.40 km) |
| Merthyr Tudful to Ridgewood (New Jersey) | 3,316.07 mi (5,336.71 km) |
| Merthyr Tudful to Rifle (Colorado) | 4,670.40 mi (7,516.29 km) |
| Merthyr Tudful to Rincon (Georgia) | 4,008.75 mi (6,451.47 km) |
| Merthyr Tudful to Ringwood (New Jersey) | 3,317.42 mi (5,338.87 km) |
| Merthyr Tudful to Río Grande (Puerto Rico) | 4,056.93 mi (6,529.01 km) |
| Merthyr Tudful to Rio Grande City (Texas) | 5,027.59 mi (8,091.12 km) |
| Merthyr Tudful to Rio Linda (California) | 5,162.99 mi (8,309.03 km) |
| Merthyr Tudful to Rio Rancho (New Mexico) | 4,856.95 mi (7,816.50 km) |
| Merthyr Tudful to Rio Rico (Arizona) | 5,216.04 mi (8,394.41 km) |
| Merthyr Tudful to Ripon (California) | 5,207.30 mi (8,380.33 km) |
| Merthyr Tudful to River Edge (New Jersey) | 3,315.39 mi (5,335.61 km) |
| Merthyr Tudful to River Falls (Wisconsin) | 3,866.95 mi (6,223.25 km) |
| Merthyr Tudful to River Forest (Illinois) | 3,822.19 mi (6,151.22 km) |
| Merthyr Tudful to River Grove (Illinois) | 3,821.56 mi (6,150.21 km) |
