| Healdsburg to Orbetello | 6,138.73 mi (9,879.34 km) |
| Healdsburg to Oria | 6,428.41 mi (10,345.53 km) |
| Healdsburg to Oristano | 6,203.94 mi (9,984.28 km) |
| Healdsburg to Orta Nova | 6,328.04 mi (10,183.99 km) |
| Healdsburg to Orte | 6,170.78 mi (9,930.92 km) |
| Healdsburg to Ortona | 6,232.70 mi (10,030.56 km) |
| Healdsburg to Orvieto | 6,148.18 mi (9,894.53 km) |
| Healdsburg to Orzinuovi | 5,934.22 mi (9,550.21 km) |
| Healdsburg to Osimo | 6,141.73 mi (9,884.15 km) |
| Healdsburg to Ospitaletto | 5,929.33 mi (9,542.34 km) |
| Healdsburg to Ostuni | 6,413.13 mi (10,320.93 km) |
| Healdsburg to Ottaviano | 6,322.71 mi (10,175.42 km) |
| Healdsburg to Ovada | 5,940.52 mi (9,560.35 km) |
| Healdsburg to Ozieri | 6,178.52 mi (9,943.36 km) |
| Healdsburg to Paceco | 6,433.99 mi (10,354.50 km) |
