| Rio Grande City to Oskaloosa (Iowa) | 1,088.85 mi (1,752.34 km) |
| Rio Grande City to Oswego (Illinois) | 1,213.62 mi (1,953.13 km) |
| Rio Grande City to Oswego (New York) | 1,718.84 mi (2,766.21 km) |
| Rio Grande City to Otsego (Minnesota) | 1,336.23 mi (2,150.46 km) |
| Rio Grande City to Ottawa (Illinois) | 1,180.95 mi (1,900.56 km) |
| Rio Grande City to Ottawa (Kansas) | 869.12 mi (1,398.71 km) |
| Rio Grande City to Ottumwa (Iowa) | 1,075.50 mi (1,730.85 km) |
| Rio Grande City to Overland (Missouri) | 981.98 mi (1,580.35 km) |
| Rio Grande City to Overland Park (Kansas) | 896.67 mi (1,443.05 km) |
| Rio Grande City to Overlea (Maryland) | 1,567.62 mi (2,522.84 km) |
| Rio Grande City to Oviedo (Florida) | 1,090.91 mi (1,755.66 km) |
| Rio Grande City to Owasso (Oklahoma) | 706.77 mi (1,137.44 km) |
| Rio Grande City to Owatonna (Minnesota) | 1,262.89 mi (2,032.42 km) |
| Rio Grande City to Owensboro (Kentucky) | 1,041.00 mi (1,675.32 km) |
| Rio Grande City to Owings Mills (Maryland) | 1,556.32 mi (2,504.65 km) |
