| Rio Grande City to Orbetello | 5,927.76 mi (9,539.81 km) |
| Rio Grande City to Oria | 6,277.40 mi (10,102.50 km) |
| Rio Grande City to Oristano | 5,903.75 mi (9,501.17 km) |
| Rio Grande City to Orta Nova | 6,162.49 mi (9,917.57 km) |
| Rio Grande City to Orte | 5,977.26 mi (9,619.46 km) |
| Rio Grande City to Ortona | 6,066.82 mi (9,763.60 km) |
| Rio Grande City to Orvieto | 5,955.77 mi (9,584.88 km) |
| Rio Grande City to Orzinuovi | 5,765.59 mi (9,278.82 km) |
| Rio Grande City to Osimo | 5,984.44 mi (9,631.03 km) |
| Rio Grande City to Ospitaletto | 5,765.79 mi (9,279.13 km) |
| Rio Grande City to Ostuni | 6,265.68 mi (10,083.63 km) |
| Rio Grande City to Ottaviano | 6,128.92 mi (9,863.55 km) |
| Rio Grande City to Ovada | 5,738.75 mi (9,235.63 km) |
| Rio Grande City to Ozieri | 5,898.14 mi (9,492.13 km) |
| Rio Grande City to Paceco | 6,154.49 mi (9,904.70 km) |
