| Southborough to Smyrna (Delaware) | 3,612.57 mi (5,813.87 km) |
| Southborough to Smyrna (Georgia) | 4,230.23 mi (6,807.89 km) |
| Southborough to Smyrna (Tennessee) | 4,209.81 mi (6,775.03 km) |
| Southborough to Snellville (Georgia) | 4,209.58 mi (6,774.66 km) |
| Southborough to Snoqualmie (Washington) | 4,805.11 mi (7,733.08 km) |
| Southborough to Snyder (Texas) | 4,934.51 mi (7,941.32 km) |
| Southborough to Socastee (South Carolina) | 4,011.03 mi (6,455.13 km) |
| Southborough to Socorro (Texas) | 5,190.67 mi (8,353.58 km) |
| Southborough to Soddy-Daisy (Tennessee) | 4,189.62 mi (6,742.54 km) |
| Southborough to Solana Beach (California) | 5,497.54 mi (8,847.44 km) |
| Southborough to Soledad (California) | 5,428.25 mi (8,735.93 km) |
| Southborough to Solon (Ohio) | 3,755.19 mi (6,043.39 km) |
| Southborough to Somers Point (New Jersey) | 3,570.29 mi (5,745.83 km) |
| Southborough to Somerset (Kentucky) | 4,079.73 mi (6,565.68 km) |
| Southborough to Somerset (New Jersey) | 3,514.02 mi (5,655.26 km) |
