| Pittsburgh to Nuth | 3,968.90 mi (6,387.33 km) |
| Pittsburgh to Oegstgeest | 3,876.80 mi (6,239.11 km) |
| Pittsburgh to Oirschot | 3,928.80 mi (6,322.79 km) |
| Pittsburgh to Oisterwijk | 3,922.47 mi (6,312.61 km) |
| Pittsburgh to Oldebroek | 3,924.24 mi (6,315.46 km) |
| Pittsburgh to Oldenzaal | 3,967.59 mi (6,385.22 km) |
| Pittsburgh to Ommen | 3,942.00 mi (6,344.03 km) |
| Pittsburgh to Oosterend | 3,914.55 mi (6,299.86 km) |
| Pittsburgh to Oosterhout | 3,907.38 mi (6,288.32 km) |
| Pittsburgh to Oosterwolde | 3,923.43 mi (6,314.15 km) |
| Pittsburgh to Oostzaan | 3,885.78 mi (6,253.56 km) |
| Pittsburgh to Opmeer | 3,880.78 mi (6,245.52 km) |
| Pittsburgh to Oss | 3,929.42 mi (6,323.79 km) |
| Pittsburgh to Oud-Beijerland | 3,884.61 mi (6,251.68 km) |
| Pittsburgh to Oudenbosch | 3,895.94 mi (6,269.92 km) |
