| Pittsburgh to Oberkirch | 4,131.31 mi (6,648.70 km) |
| Pittsburgh to Obernburg am Main | 4,130.57 mi (6,647.50 km) |
| Pittsburgh to Obernkirchen | 4,051.90 mi (6,520.90 km) |
| Pittsburgh to Oberschleissheim | 4,280.15 mi (6,888.24 km) |
| Pittsburgh to Oberstdorf | 4,257.85 mi (6,852.35 km) |
| Pittsburgh to Obertraubling | 4,278.72 mi (6,885.94 km) |
| Pittsburgh to Obertshausen | 4,111.10 mi (6,616.18 km) |
| Pittsburgh to Oberursel | 4,096.65 mi (6,592.93 km) |
| Pittsburgh to Ochsenfurt | 4,173.12 mi (6,715.99 km) |
| Pittsburgh to Ochsenhausen | 4,221.72 mi (6,794.20 km) |
| Pittsburgh to Ochtrup | 3,980.71 mi (6,406.34 km) |
| Pittsburgh to Odenthal | 4,013.55 mi (6,459.18 km) |
| Pittsburgh to Oelde | 4,028.68 mi (6,483.54 km) |
| Pittsburgh to Oelsnitz | 4,228.40 mi (6,804.96 km) |
| Pittsburgh to Oer-Erkenschwick | 4,000.09 mi (6,437.53 km) |
