| Guadarrama to Opwijk | 814.00 mi (1,310.01 km) |
| Guadarrama to Ostend | 802.23 mi (1,291.07 km) |
| Guadarrama to Oud-Heverlee | 817.85 mi (1,316.21 km) |
| Guadarrama to Oud-Turnhout | 853.21 mi (1,373.11 km) |
| Guadarrama to Oudenaarde | 793.86 mi (1,277.59 km) |
| Guadarrama to Oudenburg | 801.24 mi (1,289.48 km) |
| Guadarrama to Oupeye | 835.94 mi (1,345.31 km) |
| Guadarrama to Overijse | 811.73 mi (1,306.35 km) |
| Guadarrama to Overpelt | 858.24 mi (1,381.20 km) |
| Guadarrama to Paal | 842.11 mi (1,355.25 km) |
| Guadarrama to Peer | 854.47 mi (1,375.13 km) |
| Guadarrama to Pepinster | 832.95 mi (1,340.50 km) |
| Guadarrama to Peruwelz | 773.75 mi (1,245.22 km) |
| Guadarrama to Perwez | 809.68 mi (1,303.06 km) |
| Guadarrama to Philippeville | 779.05 mi (1,253.75 km) |
