| Difficult Run to Olivares | 3,765.17 mi (6,059.45 km) |
| Difficult Run to Olivenza | 3,681.65 mi (5,925.04 km) |
| Difficult Run to Olot | 4,037.55 mi (6,497.80 km) |
| Difficult Run to Onate | 3,786.24 mi (6,093.36 km) |
| Difficult Run to Onda | 3,975.77 mi (6,398.38 km) |
| Difficult Run to Onteniente | 3,994.15 mi (6,427.96 km) |
| Difficult Run to Orihuela | 4,000.52 mi (6,438.21 km) |
| Difficult Run to Osuna | 3,822.71 mi (6,152.06 km) |
| Difficult Run to Ourense | 3,547.99 mi (5,709.94 km) |
| Difficult Run to Oviedo | 3,617.83 mi (5,822.34 km) |
| Difficult Run to Paiporta | 3,984.65 mi (6,412.67 km) |
| Difficult Run to Pajara | 3,638.67 mi (5,855.87 km) |
| Difficult Run to Palafolls | 4,065.25 mi (6,542.39 km) |
| Difficult Run to Palafrugell | 4,076.66 mi (6,560.74 km) |
| Difficult Run to Palamos | 4,077.28 mi (6,561.75 km) |
