| Middlesex to Smyrna (Delaware) | 106.17 mi (170.87 km) |
| Middlesex to Smyrna (Georgia) | 719.35 mi (1,157.68 km) |
| Middlesex to Smyrna (Tennessee) | 724.92 mi (1,166.64 km) |
| Middlesex to Snellville (Georgia) | 698.41 mi (1,123.98 km) |
| Middlesex to Snoqualmie (Washington) | 2,361.33 mi (3,800.19 km) |
| Middlesex to Snyder (Texas) | 1,554.37 mi (2,501.52 km) |
| Middlesex to Socastee (South Carolina) | 536.55 mi (863.49 km) |
| Middlesex to Socorro (Texas) | 1,865.27 mi (3,001.86 km) |
| Middlesex to Soddy-Daisy (Tennessee) | 687.29 mi (1,106.08 km) |
| Middlesex to Solana Beach (California) | 2,398.81 mi (3,860.52 km) |
| Middlesex to Soledad (California) | 2,518.76 mi (4,053.56 km) |
| Middlesex to Solon (Ohio) | 366.16 mi (589.28 km) |
| Middlesex to Somers Point (New Jersey) | 87.08 mi (140.14 km) |
| Middlesex to Somerset (Kentucky) | 594.74 mi (957.15 km) |
| Middlesex to Somerset (New Jersey) | 4.57 mi (7.35 km) |
