| Rio Grande City to Morris (Illinois) | 1,193.10 mi (1,920.10 km) |
| Rio Grande City to Morristown (New Jersey) | 1,709.41 mi (2,751.02 km) |
| Rio Grande City to Morristown (Tennessee) | 1,137.88 mi (1,831.23 km) |
| Rio Grande City to Morrisville (North Carolina) | 1,346.97 mi (2,167.74 km) |
| Rio Grande City to Morro Bay (California) | 1,441.87 mi (2,320.46 km) |
| Rio Grande City to Morton (Illinois) | 1,119.77 mi (1,802.10 km) |
| Rio Grande City to Morton Grove (Illinois) | 1,249.80 mi (2,011.36 km) |
| Rio Grande City to Moscow (Idaho) | 1,721.37 mi (2,770.28 km) |
| Rio Grande City to Moses Lake (Washington) | 1,815.03 mi (2,921.01 km) |
| Rio Grande City to Moss Bluff (Louisiana) | 435.91 mi (701.53 km) |
| Rio Grande City to Moss Point (Mississippi) | 684.70 mi (1,101.91 km) |
| Rio Grande City to Moultrie (Georgia) | 968.43 mi (1,558.54 km) |
| Rio Grande City to Mounds View (Minnesota) | 1,330.75 mi (2,141.64 km) |
| Rio Grande City to Mount Airy (North Carolina) | 1,277.62 mi (2,056.14 km) |
| Rio Grande City to Mount Clemens (Michigan) | 1,436.79 mi (2,312.30 km) |
