| National City to Silver Firs (Washington) | 1,082.72 mi (1,742.46 km) |
| National City to Silver Spring (Maryland) | 2,268.47 mi (3,650.75 km) |
| National City to Silver Springs Shores (Florida) | 2,085.22 mi (3,355.83 km) |
| National City to Silverdale (Washington) | 1,076.85 mi (1,733.02 km) |
| National City to Silverton (Oregon) | 905.04 mi (1,456.53 km) |
| National City to Simi Valley (California) | 145.90 mi (234.80 km) |
| National City to Simpsonville (South Carolina) | 1,997.94 mi (3,215.38 km) |
| National City to Sioux City (Iowa) | 1,316.45 mi (2,118.63 km) |
| National City to Sioux Falls (South Dakota) | 1,332.41 mi (2,144.31 km) |
| National City to Skokie (Illinois) | 1,726.89 mi (2,779.16 km) |
| National City to Sleepy Hollow (New York) | 2,432.74 mi (3,915.12 km) |
| National City to Slidell (Louisiana) | 1,613.51 mi (2,596.69 km) |
| National City to Smithfield (North Carolina) | 2,211.78 mi (3,559.51 km) |
| National City to Smithfield (Utah) | 696.38 mi (1,120.71 km) |
| National City to Smithville (Missouri) | 1,337.21 mi (2,152.03 km) |
