| Potomac to Silver Firs (Washington) | 2,301.56 mi (3,704.00 km) |
| Potomac to Silver Spring (Maryland) | 9.35 mi (15.05 km) |
| Potomac to Silver Springs Shores (Florida) | 737.36 mi (1,186.67 km) |
| Potomac to Silverdale (Washington) | 2,326.75 mi (3,744.54 km) |
| Potomac to Silverton (Oregon) | 2,344.95 mi (3,773.83 km) |
| Potomac to Simi Valley (California) | 2,306.91 mi (3,712.62 km) |
| Potomac to Simpsonville (South Carolina) | 407.26 mi (655.42 km) |
| Potomac to Sioux City (Iowa) | 1,030.64 mi (1,658.65 km) |
| Potomac to Sioux Falls (South Dakota) | 1,058.67 mi (1,703.76 km) |
| Potomac to Skokie (Illinois) | 591.40 mi (951.77 km) |
| Potomac to Sleepy Hollow (New York) | 226.93 mi (365.21 km) |
| Potomac to Slidell (Louisiana) | 933.98 mi (1,503.09 km) |
| Potomac to Smithfield (North Carolina) | 250.08 mi (402.46 km) |
| Potomac to Smithfield (Utah) | 1,819.58 mi (2,928.33 km) |
| Potomac to Smithville (Missouri) | 929.50 mi (1,495.88 km) |
