| Middle River to Olivares | 3,707.88 mi (5,967.26 km) |
| Middle River to Olivenza | 3,624.19 mi (5,832.58 km) |
| Middle River to Olot | 3,979.47 mi (6,404.33 km) |
| Middle River to Onate | 3,728.18 mi (5,999.92 km) |
| Middle River to Onda | 3,917.85 mi (6,305.16 km) |
| Middle River to Onteniente | 3,936.34 mi (6,334.93 km) |
| Middle River to Orihuela | 3,942.82 mi (6,345.35 km) |
| Middle River to Osuna | 3,765.38 mi (6,059.80 km) |
| Middle River to Ourense | 3,490.08 mi (5,616.74 km) |
| Middle River to Oviedo | 3,559.80 mi (5,728.95 km) |
| Middle River to Paiporta | 3,926.78 mi (6,319.54 km) |
| Middle River to Pajara | 3,585.36 mi (5,770.08 km) |
| Middle River to Palafolls | 4,007.18 mi (6,448.93 km) |
| Middle River to Palafrugell | 4,018.58 mi (6,467.27 km) |
| Middle River to Palamos | 4,019.21 mi (6,468.29 km) |
