| South Portland to Sestu | 3,959.02 mi (6,371.42 km) |
| South Portland to Settimo Torinese | 3,697.01 mi (5,949.76 km) |
| South Portland to Seveso | 3,738.74 mi (6,016.92 km) |
| South Portland to Sezze | 4,053.86 mi (6,524.05 km) |
| South Portland to Siano | 4,151.10 mi (6,680.55 km) |
| South Portland to Siena | 3,912.39 mi (6,296.38 km) |
| South Portland to Signa | 3,885.99 mi (6,253.90 km) |
| South Portland to Silea | 3,871.41 mi (6,230.43 km) |
| South Portland to Silvi Paese | 4,060.11 mi (6,534.11 km) |
| South Portland to Sinalunga | 3,933.33 mi (6,330.08 km) |
| South Portland to Siniscola | 3,939.41 mi (6,339.87 km) |
| South Portland to Sinnai | 3,963.93 mi (6,379.32 km) |
| South Portland to Siracusa | 4,324.07 mi (6,958.92 km) |
| South Portland to Solaro | 3,737.41 mi (6,014.78 km) |
| South Portland to Soliera | 3,845.23 mi (6,188.30 km) |
