| Marinha Grande to Orbetello | 1,062.71 mi (1,710.26 km) |
| Marinha Grande to Oria | 1,399.20 mi (2,251.80 km) |
| Marinha Grande to Oristano | 928.47 mi (1,494.22 km) |
| Marinha Grande to Orta Nova | 1,294.26 mi (2,082.90 km) |
| Marinha Grande to Orte | 1,122.53 mi (1,806.54 km) |
| Marinha Grande to Ortona | 1,225.05 mi (1,971.52 km) |
| Marinha Grande to Orvieto | 1,109.45 mi (1,785.48 km) |
| Marinha Grande to Orzinuovi | 1,033.15 mi (1,662.69 km) |
| Marinha Grande to Osimo | 1,182.42 mi (1,902.92 km) |
| Marinha Grande to Ospitaletto | 1,042.58 mi (1,677.87 km) |
| Marinha Grande to Ostuni | 1,394.84 mi (2,244.78 km) |
| Marinha Grande to Ottaviano | 1,232.30 mi (1,983.20 km) |
| Marinha Grande to Ovada | 958.82 mi (1,543.07 km) |
| Marinha Grande to Ozieri | 947.14 mi (1,524.28 km) |
| Marinha Grande to Paceco | 1,159.35 mi (1,865.80 km) |
