| Herndon to Silver Firs (Washington) | 2,294.19 mi (3,692.14 km) |
| Herndon to Silver Spring (Maryland) | 19.79 mi (31.84 km) |
| Herndon to Silver Springs Shores (Florida) | 730.51 mi (1,175.65 km) |
| Herndon to Silverdale (Washington) | 2,319.33 mi (3,732.60 km) |
| Herndon to Silverton (Oregon) | 2,336.91 mi (3,760.89 km) |
| Herndon to Simi Valley (California) | 2,296.89 mi (3,696.48 km) |
| Herndon to Simpsonville (South Carolina) | 397.84 mi (640.26 km) |
| Herndon to Sioux City (Iowa) | 1,021.95 mi (1,644.67 km) |
| Herndon to Sioux Falls (South Dakota) | 1,050.42 mi (1,690.48 km) |
| Herndon to Skokie (Illinois) | 583.24 mi (938.64 km) |
| Herndon to Sleepy Hollow (New York) | 236.82 mi (381.13 km) |
| Herndon to Slidell (Louisiana) | 923.86 mi (1,486.81 km) |
| Herndon to Smithfield (North Carolina) | 244.62 mi (393.68 km) |
| Herndon to Smithfield (Utah) | 1,810.63 mi (2,913.93 km) |
| Herndon to Smithville (Missouri) | 919.63 mi (1,480.00 km) |
