| Rio Grande City to Silver Firs (Washington) | 1,947.67 mi (3,134.47 km) |
| Rio Grande City to Silver Spring (Maryland) | 1,532.07 mi (2,465.63 km) |
| Rio Grande City to Silver Springs Shores (Florida) | 1,043.92 mi (1,680.03 km) |
| Rio Grande City to Silverdale (Washington) | 1,957.52 mi (3,150.32 km) |
| Rio Grande City to Silverton (Oregon) | 1,847.50 mi (2,973.26 km) |
| Rio Grande City to Simi Valley (California) | 1,304.28 mi (2,099.04 km) |
| Rio Grande City to Simpsonville (South Carolina) | 1,139.64 mi (1,834.07 km) |
| Rio Grande City to Sioux City (Iowa) | 1,121.90 mi (1,805.52 km) |
| Rio Grande City to Sioux Falls (South Dakota) | 1,191.34 mi (1,917.28 km) |
| Rio Grande City to Skokie (Illinois) | 1,250.83 mi (2,013.01 km) |
| Rio Grande City to Sleepy Hollow (New York) | 1,746.91 mi (2,811.38 km) |
| Rio Grande City to Slidell (Louisiana) | 612.13 mi (985.13 km) |
| Rio Grande City to Smithfield (North Carolina) | 1,363.50 mi (2,194.34 km) |
| Rio Grande City to Smithfield (Utah) | 1,298.04 mi (2,088.99 km) |
| Rio Grande City to Smithville (Missouri) | 931.82 mi (1,499.61 km) |
