| Llantwit Major to Silver Firs (Washington) | 4,680.54 mi (7,532.60 km) |
| Llantwit Major to Silver Spring (Maryland) | 3,524.33 mi (5,671.87 km) |
| Llantwit Major to Silver Springs Shores (Florida) | 4,197.76 mi (6,755.65 km) |
| Llantwit Major to Silverdale (Washington) | 4,706.14 mi (7,573.80 km) |
| Llantwit Major to Silverton (Oregon) | 4,858.48 mi (7,818.96 km) |
| Llantwit Major to Simi Valley (California) | 5,340.43 mi (8,594.60 km) |
| Llantwit Major to Simpsonville (South Carolina) | 3,936.61 mi (6,335.36 km) |
| Llantwit Major to Sioux City (Iowa) | 4,124.53 mi (6,637.79 km) |
| Llantwit Major to Sioux Falls (South Dakota) | 4,087.21 mi (6,577.73 km) |
| Llantwit Major to Skokie (Illinois) | 3,819.09 mi (6,146.24 km) |
| Llantwit Major to Sleepy Hollow (New York) | 3,304.09 mi (5,317.42 km) |
| Llantwit Major to Slidell (Louisiana) | 4,463.64 mi (7,183.54 km) |
| Llantwit Major to Smithfield (North Carolina) | 3,737.28 mi (6,014.57 km) |
| Llantwit Major to Smithfield (Utah) | 4,696.76 mi (7,558.71 km) |
| Llantwit Major to Smithville (Missouri) | 4,205.86 mi (6,768.67 km) |
