| Union to Orbetello | 5,023.31 mi (8,084.24 km) |
| Union to Oria | 5,366.52 mi (8,636.58 km) |
| Union to Oristano | 5,017.20 mi (8,074.40 km) |
| Union to Orta Nova | 5,252.75 mi (8,453.48 km) |
| Union to Orte | 5,070.22 mi (8,159.73 km) |
| Union to Ortona | 5,155.99 mi (8,297.77 km) |
| Union to Orvieto | 5,048.27 mi (8,124.40 km) |
| Union to Orzinuovi | 4,851.69 mi (7,808.04 km) |
| Union to Osimo | 5,071.19 mi (8,161.30 km) |
| Union to Ospitaletto | 4,851.04 mi (7,807.00 km) |
| Union to Ostuni | 5,354.06 mi (8,616.52 km) |
| Union to Ottaviano | 5,223.81 mi (8,406.91 km) |
| Union to Ovada | 4,830.26 mi (7,773.56 km) |
| Union to Ozieri | 5,007.19 mi (8,058.29 km) |
| Union to Paceco | 5,266.91 mi (8,476.27 km) |
