| Allentown to Silver Firs (Washington) | 2,327.53 mi (3,745.80 km) |
| Allentown to Silver Spring (Maryland) | 137.28 mi (220.92 km) |
| Allentown to Silver Springs Shores (Florida) | 875.11 mi (1,408.36 km) |
| Allentown to Silverdale (Washington) | 2,353.48 mi (3,787.56 km) |
| Allentown to Silverton (Oregon) | 2,383.10 mi (3,835.22 km) |
| Allentown to Simi Valley (California) | 2,389.66 mi (3,845.79 km) |
| Allentown to Simpsonville (South Carolina) | 549.11 mi (883.71 km) |
| Allentown to Sioux City (Iowa) | 1,086.64 mi (1,748.78 km) |
| Allentown to Sioux Falls (South Dakota) | 1,105.85 mi (1,779.69 km) |
| Allentown to Skokie (Illinois) | 643.60 mi (1,035.78 km) |
| Allentown to Sleepy Hollow (New York) | 90.58 mi (145.77 km) |
| Allentown to Slidell (Louisiana) | 1,072.49 mi (1,726.00 km) |
| Allentown to Smithfield (North Carolina) | 384.36 mi (618.57 km) |
| Allentown to Smithfield (Utah) | 1,877.11 mi (3,020.91 km) |
| Allentown to Smithville (Missouri) | 1,012.40 mi (1,629.30 km) |
