| Merthyr Tudful to Superior (Colorado) | 4,558.52 mi (7,336.23 km) |
| Merthyr Tudful to Superior (Wisconsin) | 3,764.02 mi (6,057.60 km) |
| Merthyr Tudful to Surprise (Arizona) | 5,148.01 mi (8,284.92 km) |
| Merthyr Tudful to Susanville (California) | 5,039.49 mi (8,110.28 km) |
| Merthyr Tudful to Sussex (Wisconsin) | 3,781.22 mi (6,085.28 km) |
| Merthyr Tudful to Suwanee (Georgia) | 4,041.17 mi (6,503.64 km) |
| Merthyr Tudful to Swansea (Illinois) | 4,062.72 mi (6,538.31 km) |
| Merthyr Tudful to Sweetwater (Florida) | 4,295.12 mi (6,912.33 km) |
| Merthyr Tudful to Sweetwater (Texas) | 4,770.66 mi (7,677.64 km) |
| Merthyr Tudful to Sycamore (Illinois) | 3,850.74 mi (6,197.16 km) |
| Merthyr Tudful to Sylacauga (Alabama) | 4,173.29 mi (6,716.26 km) |
| Merthyr Tudful to Sylvania (Ohio) | 3,670.43 mi (5,906.98 km) |
| Merthyr Tudful to Syosset (New York) | 3,298.08 mi (5,307.75 km) |
| Merthyr Tudful to Syracuse (New York) | 3,311.73 mi (5,329.71 km) |
| Merthyr Tudful to Syracuse (Utah) | 4,732.96 mi (7,616.96 km) |
