| Potomac to Smyrna (Delaware) | 87.14 mi (140.24 km) |
| Potomac to Smyrna (Georgia) | 540.32 mi (869.56 km) |
| Potomac to Smyrna (Tennessee) | 552.83 mi (889.70 km) |
| Potomac to Snellville (Georgia) | 519.59 mi (836.19 km) |
| Potomac to Snoqualmie (Washington) | 2,287.89 mi (3,682.01 km) |
| Potomac to Snyder (Texas) | 1,392.80 mi (2,241.49 km) |
| Potomac to Socastee (South Carolina) | 381.63 mi (614.18 km) |
| Potomac to Socorro (Texas) | 1,707.48 mi (2,747.92 km) |
| Potomac to Soddy-Daisy (Tennessee) | 510.17 mi (821.03 km) |
| Potomac to Solana Beach (California) | 2,258.99 mi (3,635.50 km) |
| Potomac to Soledad (California) | 2,395.46 mi (3,855.13 km) |
| Potomac to Solon (Ohio) | 277.56 mi (446.69 km) |
| Potomac to Somers Point (New Jersey) | 140.19 mi (225.61 km) |
| Potomac to Somerset (Kentucky) | 424.86 mi (683.75 km) |
| Potomac to Somerset (New Jersey) | 176.40 mi (283.89 km) |
