| Mason City to Silver Firs (Washington) | 1,430.14 mi (2,301.58 km) |
| Mason City to Silver Spring (Maryland) | 888.33 mi (1,429.62 km) |
| Mason City to Silver Springs Shores (Florida) | 1,150.91 mi (1,852.20 km) |
| Mason City to Silverdale (Washington) | 1,454.43 mi (2,340.68 km) |
| Mason City to Silverton (Oregon) | 1,465.72 mi (2,358.85 km) |
| Mason City to Simi Valley (California) | 1,500.23 mi (2,414.39 km) |
| Mason City to Simpsonville (South Carolina) | 825.86 mi (1,329.09 km) |
| Mason City to Sioux City (Iowa) | 167.84 mi (270.12 km) |
| Mason City to Sioux Falls (South Dakota) | 179.47 mi (288.84 km) |
| Mason City to Skokie (Illinois) | 288.09 mi (463.64 km) |
| Mason City to Sleepy Hollow (New York) | 998.35 mi (1,606.68 km) |
| Mason City to Slidell (Louisiana) | 908.25 mi (1,461.68 km) |
| Mason City to Smithfield (North Carolina) | 950.77 mi (1,530.11 km) |
| Mason City to Smithfield (Utah) | 951.34 mi (1,531.04 km) |
| Mason City to Smithville (Missouri) | 269.20 mi (433.24 km) |
