| Potomac to Sestu | 4,425.09 mi (7,121.50 km) |
| Potomac to Settimo Torinese | 4,171.55 mi (6,713.47 km) |
| Potomac to Seveso | 4,214.48 mi (6,782.54 km) |
| Potomac to Sezze | 4,526.56 mi (7,284.79 km) |
| Potomac to Siano | 4,623.91 mi (7,441.47 km) |
| Potomac to Siena | 4,386.44 mi (7,059.29 km) |
| Potomac to Signa | 4,360.49 mi (7,017.53 km) |
| Potomac to Silea | 4,348.33 mi (6,997.96 km) |
| Potomac to Silvi Paese | 4,534.71 mi (7,297.91 km) |
| Potomac to Sinalunga | 4,407.46 mi (7,093.13 km) |
| Potomac to Siniscola | 4,408.32 mi (7,094.50 km) |
| Potomac to Sinnai | 4,430.11 mi (7,129.57 km) |
| Potomac to Siracusa | 4,791.82 mi (7,711.69 km) |
| Potomac to Solaro | 4,213.09 mi (6,780.32 km) |
| Potomac to Soliera | 4,320.73 mi (6,953.55 km) |
