| Potomac to Nyon | 4,066.99 mi (6,545.19 km) |
| Potomac to Oberriet | 4,179.68 mi (6,726.55 km) |
| Potomac to Obersiggenthal | 4,121.11 mi (6,632.29 km) |
| Potomac to Oberwil | 4,089.35 mi (6,581.17 km) |
| Potomac to Oberwingert | 4,140.15 mi (6,662.93 km) |
| Potomac to Oftringen | 4,110.52 mi (6,615.24 km) |
| Potomac to Olten | 4,108.80 mi (6,612.48 km) |
| Potomac to Onex | 4,067.23 mi (6,545.57 km) |
| Potomac to Opfikon | 4,134.25 mi (6,653.44 km) |
| Potomac to Ostermundigen | 4,103.42 mi (6,603.82 km) |
| Potomac to Payerne | 4,083.96 mi (6,572.51 km) |
| Potomac to Pfaffikon | 4,145.37 mi (6,671.33 km) |
| Potomac to Plan-les-Ouates | 4,068.44 mi (6,547.52 km) |
| Potomac to Pratteln | 4,095.36 mi (6,590.85 km) |
| Potomac to Prilly | 4,078.23 mi (6,563.28 km) |
