| Merthyr Tudful to Southern Pines (North Carolina) | 3,794.46 mi (6,106.59 km) |
| Merthyr Tudful to Southfield (Michigan) | 3,618.77 mi (5,823.85 km) |
| Merthyr Tudful to Southgate (Michigan) | 3,628.63 mi (5,839.71 km) |
| Merthyr Tudful to Southlake (Texas) | 4,619.63 mi (7,434.58 km) |
| Merthyr Tudful to Spanaway (Washington) | 4,715.61 mi (7,589.04 km) |
| Merthyr Tudful to Spanish Fork (Utah) | 4,771.13 mi (7,678.39 km) |
| Merthyr Tudful to Spanish Lake (Missouri) | 4,060.02 mi (6,533.97 km) |
| Merthyr Tudful to Spanish Springs (Nevada) | 5,053.70 mi (8,133.14 km) |
| Merthyr Tudful to Sparks (Nevada) | 5,059.82 mi (8,143.00 km) |
| Merthyr Tudful to Spartanburg (South Carolina) | 3,910.35 mi (6,293.10 km) |
| Merthyr Tudful to Spearfish (South Dakota) | 4,280.19 mi (6,888.30 km) |
| Merthyr Tudful to Speedway (Indiana) | 3,857.60 mi (6,208.21 km) |
| Merthyr Tudful to Spencer (Iowa) | 4,039.60 mi (6,501.11 km) |
| Merthyr Tudful to Spokane (Washington) | 4,543.76 mi (7,312.48 km) |
| Merthyr Tudful to Spokane Valley (Washington) | 4,538.28 mi (7,303.65 km) |
