| Rio Grande City to Marrero (Louisiana) | 583.07 mi (938.37 km) |
| Rio Grande City to Marshall (Minnesota) | 1,259.75 mi (2,027.38 km) |
| Rio Grande City to Marshall (Missouri) | 937.96 mi (1,509.50 km) |
| Rio Grande City to Marshall (Texas) | 503.09 mi (809.64 km) |
| Rio Grande City to Marshalltown (Iowa) | 1,132.36 mi (1,822.36 km) |
| Rio Grande City to Marshfield (Wisconsin) | 1,351.61 mi (2,175.21 km) |
| Rio Grande City to Martha Lake (Washington) | 1,949.85 mi (3,137.98 km) |
| Rio Grande City to Martin (Tennessee) | 904.05 mi (1,454.93 km) |
| Rio Grande City to Martinez (California) | 1,574.28 mi (2,533.56 km) |
| Rio Grande City to Martinez (Georgia) | 1,114.13 mi (1,793.02 km) |
| Rio Grande City to Martinsburg (West Virginia) | 1,502.91 mi (2,418.71 km) |
| Rio Grande City to Martinsville (Indiana) | 1,149.80 mi (1,850.42 km) |
| Rio Grande City to Martinsville (New Jersey) | 1,698.60 mi (2,733.64 km) |
| Rio Grande City to Martinsville (Virginia) | 1,320.16 mi (2,124.59 km) |
| Rio Grande City to Maryland City (Maryland) | 1,545.49 mi (2,487.23 km) |
