| Merthyr Tudful to San Luis Obispo (California) | 5,333.85 mi (8,583.99 km) |
| Merthyr Tudful to San Marcos (California) | 5,340.22 mi (8,594.26 km) |
| Merthyr Tudful to San Marcos (Texas) | 4,809.40 mi (7,739.98 km) |
| Merthyr Tudful to San Marino (California) | 5,315.88 mi (8,555.08 km) |
| Merthyr Tudful to San Mateo (California) | 5,254.46 mi (8,456.23 km) |
| Merthyr Tudful to San Pablo (California) | 5,231.85 mi (8,419.86 km) |
| Merthyr Tudful to San Rafael (California) | 5,235.73 mi (8,426.10 km) |
| Merthyr Tudful to San Ramon (California) | 5,230.92 mi (8,418.36 km) |
| Merthyr Tudful to San Tan Valley (Arizona) | 5,144.37 mi (8,279.06 km) |
| Merthyr Tudful to Sand Springs (Oklahoma) | 4,418.95 mi (7,111.61 km) |
| Merthyr Tudful to Sandusky (Ohio) | 3,642.41 mi (5,861.89 km) |
| Merthyr Tudful to Sandy (Oregon) | 4,806.93 mi (7,736.01 km) |
| Merthyr Tudful to Sandy (Utah) | 4,753.36 mi (7,649.80 km) |
| Merthyr Tudful to Sandy Springs (Georgia) | 4,059.05 mi (6,532.42 km) |
| Merthyr Tudful to Sanford (Florida) | 4,182.37 mi (6,730.87 km) |
