| Pontypridd to Silver Firs (Washington) | 4,673.74 mi (7,521.65 km) |
| Pontypridd to Silver Spring (Maryland) | 3,525.99 mi (5,674.53 km) |
| Pontypridd to Silver Springs Shores (Florida) | 4,200.78 mi (6,760.50 km) |
| Pontypridd to Silverdale (Washington) | 4,699.29 mi (7,562.78 km) |
| Pontypridd to Silverton (Oregon) | 4,851.99 mi (7,808.53 km) |
| Pontypridd to Simi Valley (California) | 5,336.11 mi (8,587.64 km) |
| Pontypridd to Simpsonville (South Carolina) | 3,938.40 mi (6,338.23 km) |
| Pontypridd to Sioux City (Iowa) | 4,122.35 mi (6,634.28 km) |
| Pontypridd to Sioux Falls (South Dakota) | 4,084.76 mi (6,573.79 km) |
| Pontypridd to Skokie (Illinois) | 3,818.32 mi (6,144.99 km) |
| Pontypridd to Sleepy Hollow (New York) | 3,305.70 mi (5,320.01 km) |
| Pontypridd to Slidell (Louisiana) | 4,465.04 mi (7,185.78 km) |
| Pontypridd to Smithfield (North Carolina) | 3,739.55 mi (6,018.23 km) |
| Pontypridd to Smithfield (Utah) | 4,692.37 mi (7,551.65 km) |
| Pontypridd to Smithville (Missouri) | 4,204.61 mi (6,766.66 km) |
