| Castle Rock to Olivares | 5,042.99 mi (8,115.91 km) |
| Castle Rock to Olivenza | 4,949.19 mi (7,964.96 km) |
| Castle Rock to Olot | 5,196.58 mi (8,363.09 km) |
| Castle Rock to Onate | 4,965.42 mi (7,991.06 km) |
| Castle Rock to Onda | 5,184.40 mi (8,343.49 km) |
| Castle Rock to Onteniente | 5,220.10 mi (8,400.94 km) |
| Castle Rock to Orihuela | 5,238.11 mi (8,429.93 km) |
| Castle Rock to Osuna | 5,096.59 mi (8,202.17 km) |
| Castle Rock to Ourense | 4,770.16 mi (7,676.84 km) |
| Castle Rock to Oviedo | 4,813.11 mi (7,745.95 km) |
| Castle Rock to Paiporta | 5,201.43 mi (8,370.89 km) |
| Castle Rock to Pajara | 5,044.08 mi (8,117.66 km) |
| Castle Rock to Palafolls | 5,229.79 mi (8,416.53 km) |
| Castle Rock to Palafrugell | 5,234.77 mi (8,424.54 km) |
| Castle Rock to Palamos | 5,236.66 mi (8,427.59 km) |
