| Middle River to Orbetello | 4,364.68 mi (7,024.27 km) |
| Middle River to Oria | 4,717.53 mi (7,592.13 km) |
| Middle River to Oristano | 4,333.98 mi (6,974.87 km) |
| Middle River to Orta Nova | 4,602.14 mi (7,406.43 km) |
| Middle River to Orte | 4,415.61 mi (7,106.24 km) |
| Middle River to Ortona | 4,507.53 mi (7,254.16 km) |
| Middle River to Orvieto | 4,394.48 mi (7,072.23 km) |
| Middle River to Orzinuovi | 4,209.80 mi (6,775.01 km) |
| Middle River to Osimo | 4,427.32 mi (7,125.08 km) |
| Middle River to Ospitaletto | 4,210.75 mi (6,776.55 km) |
| Middle River to Ostuni | 4,706.38 mi (7,574.19 km) |
| Middle River to Ottaviano | 4,565.73 mi (7,347.83 km) |
| Middle River to Ovada | 4,178.77 mi (6,725.08 km) |
| Middle River to Ozieri | 4,329.45 mi (6,967.58 km) |
| Middle River to Paceco | 4,584.70 mi (7,378.36 km) |
