| Rio Grande City to Smyrna (Delaware) | 1,608.50 mi (2,588.63 km) |
| Rio Grande City to Smyrna (Georgia) | 997.53 mi (1,605.37 km) |
| Rio Grande City to Smyrna (Tennessee) | 981.84 mi (1,580.11 km) |
| Rio Grande City to Snellville (Georgia) | 1,023.56 mi (1,647.26 km) |
| Rio Grande City to Snoqualmie (Washington) | 1,921.64 mi (3,092.59 km) |
| Rio Grande City to Snyder (Texas) | 455.18 mi (732.54 km) |
| Rio Grande City to Socastee (South Carolina) | 1,285.31 mi (2,068.50 km) |
| Rio Grande City to Socorro (Texas) | 577.62 mi (929.59 km) |
| Rio Grande City to Soddy-Daisy (Tennessee) | 1,014.09 mi (1,632.02 km) |
| Rio Grande City to Solana Beach (California) | 1,195.01 mi (1,923.19 km) |
| Rio Grande City to Soledad (California) | 1,493.68 mi (2,403.85 km) |
| Rio Grande City to Solon (Ohio) | 1,432.87 mi (2,305.98 km) |
| Rio Grande City to Somers Point (New Jersey) | 1,657.33 mi (2,667.22 km) |
| Rio Grande City to Somerset (Kentucky) | 1,113.03 mi (1,791.25 km) |
| Rio Grande City to Somerset (New Jersey) | 1,699.01 mi (2,734.29 km) |
