| Llantrisant to Silver Firs (Washington) | 4,676.04 mi (7,525.35 km) |
| Llantrisant to Silver Spring (Maryland) | 3,525.80 mi (5,674.23 km) |
| Llantrisant to Silver Springs Shores (Florida) | 4,200.18 mi (6,759.54 km) |
| Llantrisant to Silverdale (Washington) | 4,701.60 mi (7,566.50 km) |
| Llantrisant to Silverton (Oregon) | 4,854.20 mi (7,812.08 km) |
| Llantrisant to Simi Valley (California) | 5,337.70 mi (8,590.19 km) |
| Llantrisant to Simpsonville (South Carolina) | 3,938.17 mi (6,337.87 km) |
| Llantrisant to Sioux City (Iowa) | 4,123.31 mi (6,635.82 km) |
| Llantrisant to Sioux Falls (South Dakota) | 4,085.79 mi (6,575.45 km) |
| Llantrisant to Skokie (Illinois) | 3,818.86 mi (6,145.86 km) |
| Llantrisant to Sleepy Hollow (New York) | 3,305.53 mi (5,319.73 km) |
| Llantrisant to Slidell (Louisiana) | 4,464.93 mi (7,185.61 km) |
| Llantrisant to Smithfield (North Carolina) | 3,739.18 mi (6,017.63 km) |
| Llantrisant to Smithfield (Utah) | 4,693.98 mi (7,554.22 km) |
| Llantrisant to Smithville (Missouri) | 4,205.29 mi (6,767.76 km) |
