| Grayslake to Olivares | 4,181.49 mi (6,729.46 km) |
| Grayslake to Olivenza | 4,090.90 mi (6,583.67 km) |
| Grayslake to Olot | 4,382.66 mi (7,053.21 km) |
| Grayslake to Onate | 4,141.36 mi (6,664.88 km) |
| Grayslake to Onda | 4,349.96 mi (7,000.58 km) |
| Grayslake to Onteniente | 4,379.01 mi (7,047.33 km) |
| Grayslake to Orihuela | 4,392.59 mi (7,069.20 km) |
| Grayslake to Osuna | 4,236.76 mi (6,818.41 km) |
| Grayslake to Ourense | 3,927.68 mi (6,320.99 km) |
| Grayslake to Oviedo | 3,981.43 mi (6,407.49 km) |
| Grayslake to Paiporta | 4,363.85 mi (7,022.93 km) |
| Grayslake to Pajara | 4,146.25 mi (6,672.74 km) |
| Grayslake to Palafolls | 4,413.79 mi (7,103.32 km) |
| Grayslake to Palafrugell | 4,421.53 mi (7,115.76 km) |
| Grayslake to Palamos | 4,422.90 mi (7,117.96 km) |
