| Pittsburgh to Olivares | 3,853.40 mi (6,201.45 km) |
| Pittsburgh to Olivenza | 3,767.22 mi (6,062.75 km) |
| Pittsburgh to Olot | 4,101.97 mi (6,601.49 km) |
| Pittsburgh to Onate | 3,853.42 mi (6,201.49 km) |
| Pittsburgh to Onda | 4,049.85 mi (6,517.61 km) |
| Pittsburgh to Onteniente | 4,071.92 mi (6,553.12 km) |
| Pittsburgh to Orihuela | 4,080.78 mi (6,567.38 km) |
| Pittsburgh to Osuna | 3,910.26 mi (6,292.95 km) |
| Pittsburgh to Ourense | 3,622.96 mi (5,830.60 km) |
| Pittsburgh to Oviedo | 3,687.47 mi (5,934.40 km) |
| Pittsburgh to Paiporta | 4,060.46 mi (6,534.68 km) |
| Pittsburgh to Pajara | 3,760.40 mi (6,051.77 km) |
| Pittsburgh to Palafolls | 4,130.89 mi (6,648.02 km) |
| Pittsburgh to Palafrugell | 4,141.09 mi (6,664.44 km) |
| Pittsburgh to Palamos | 4,141.97 mi (6,665.86 km) |
