| Fort Madison to Silver Firs (Washington) | 1,592.20 mi (2,562.39 km) |
| Fort Madison to Silver Spring (Maryland) | 767.85 mi (1,235.74 km) |
| Fort Madison to Silver Springs Shores (Florida) | 953.85 mi (1,535.07 km) |
| Fort Madison to Silverdale (Washington) | 1,615.29 mi (2,599.56 km) |
| Fort Madison to Silverton (Oregon) | 1,611.01 mi (2,592.68 km) |
| Fort Madison to Simi Valley (California) | 1,558.59 mi (2,508.30 km) |
| Fort Madison to Simpsonville (South Carolina) | 642.07 mi (1,033.31 km) |
| Fort Madison to Sioux City (Iowa) | 290.90 mi (468.16 km) |
| Fort Madison to Sioux Falls (South Dakota) | 341.64 mi (549.81 km) |
| Fort Madison to Skokie (Illinois) | 211.31 mi (340.07 km) |
| Fort Madison to Sleepy Hollow (New York) | 912.46 mi (1,468.46 km) |
| Fort Madison to Slidell (Louisiana) | 719.27 mi (1,157.55 km) |
| Fort Madison to Smithfield (North Carolina) | 789.27 mi (1,270.21 km) |
| Fort Madison to Smithfield (Utah) | 1,064.78 mi (1,713.59 km) |
| Fort Madison to Smithville (Missouri) | 190.56 mi (306.67 km) |
