| Middlesex to Silver Firs (Washington) | 2,373.21 mi (3,819.31 km) |
| Middlesex to Silver Spring (Maryland) | 172.28 mi (277.26 km) |
| Middlesex to Silver Springs Shores (Florida) | 898.40 mi (1,445.84 km) |
| Middlesex to Silverdale (Washington) | 2,399.27 mi (3,861.26 km) |
| Middlesex to Silverton (Oregon) | 2,430.58 mi (3,911.64 km) |
| Middlesex to Simi Valley (California) | 2,440.78 mi (3,928.05 km) |
| Middlesex to Simpsonville (South Carolina) | 585.32 mi (941.99 km) |
| Middlesex to Sioux City (Iowa) | 1,136.65 mi (1,829.25 km) |
| Middlesex to Sioux Falls (South Dakota) | 1,155.05 mi (1,858.87 km) |
| Middlesex to Skokie (Illinois) | 693.80 mi (1,116.56 km) |
| Middlesex to Sleepy Hollow (New York) | 48.66 mi (78.31 km) |
| Middlesex to Slidell (Louisiana) | 1,112.98 mi (1,791.16 km) |
| Middlesex to Smithfield (North Carolina) | 407.49 mi (655.79 km) |
| Middlesex to Smithfield (Utah) | 1,926.91 mi (3,101.07 km) |
| Middlesex to Smithville (Missouri) | 1,063.55 mi (1,711.62 km) |
