| Portsmouth to Silver Firs (Washington) | 4,777.70 mi (7,688.96 km) |
| Portsmouth to Silver Spring (Maryland) | 3,635.59 mi (5,850.92 km) |
| Portsmouth to Silver Springs Shores (Florida) | 4,307.74 mi (6,932.63 km) |
| Portsmouth to Silverdale (Washington) | 4,803.11 mi (7,729.86 km) |
| Portsmouth to Silverton (Oregon) | 4,956.93 mi (7,977.41 km) |
| Portsmouth to Simi Valley (California) | 5,445.90 mi (8,764.34 km) |
| Portsmouth to Simpsonville (South Carolina) | 4,047.78 mi (6,514.27 km) |
| Portsmouth to Sioux City (Iowa) | 4,234.25 mi (6,814.36 km) |
| Portsmouth to Sioux Falls (South Dakota) | 4,196.53 mi (6,753.66 km) |
| Portsmouth to Skokie (Illinois) | 3,930.25 mi (6,325.12 km) |
| Portsmouth to Sleepy Hollow (New York) | 3,415.37 mi (5,496.51 km) |
| Portsmouth to Slidell (Louisiana) | 4,575.02 mi (7,362.79 km) |
| Portsmouth to Smithfield (North Carolina) | 3,848.07 mi (6,192.88 km) |
| Portsmouth to Smithfield (Utah) | 4,802.08 mi (7,728.20 km) |
| Portsmouth to Smithville (Missouri) | 4,316.64 mi (6,946.96 km) |
