| Oristano to Olympia Heights (Florida) | 5,048.05 mi (8,124.06 km) |
| Oristano to Omaha (Nebraska) | 5,106.00 mi (8,217.32 km) |
| Oristano to On Top of the World Designated Place (Florida) | 5,004.80 mi (8,054.44 km) |
| Oristano to Onalaska (Wisconsin) | 4,800.11 mi (7,725.03 km) |
| Oristano to Oneida (New York) | 4,171.83 mi (6,713.91 km) |
| Oristano to Oneonta (New York) | 4,165.88 mi (6,704.34 km) |
| Oristano to Ontario (California) | 6,282.95 mi (10,111.42 km) |
| Oristano to Ontario (Oregon) | 5,722.15 mi (9,208.91 km) |
| Oristano to Opa-locka (Florida) | 5,036.63 mi (8,105.67 km) |
| Oristano to Opelika (Alabama) | 5,005.89 mi (8,056.20 km) |
| Oristano to Opelousas (Louisiana) | 5,407.28 mi (8,702.18 km) |
| Oristano to Orange (California) | 6,303.37 mi (10,144.29 km) |
| Oristano to Orange (Texas) | 5,501.86 mi (8,854.39 km) |
| Oristano to Orange City (Florida) | 4,963.17 mi (7,987.45 km) |
| Oristano to Orangeburg (South Carolina) | 4,760.26 mi (7,660.90 km) |
