| Fairfield to Olympia Heights (Florida) | 2,567.32 mi (4,131.71 km) |
| Fairfield to Omaha (Nebraska) | 1,390.13 mi (2,237.20 km) |
| Fairfield to On Top of the World Designated Place (Florida) | 2,351.55 mi (3,784.46 km) |
| Fairfield to Onalaska (Wisconsin) | 1,641.78 mi (2,642.18 km) |
| Fairfield to Oneida (New York) | 2,421.71 mi (3,897.37 km) |
| Fairfield to Oneonta (New York) | 2,458.16 mi (3,956.03 km) |
| Fairfield to Ontario (California) | 381.97 mi (614.72 km) |
| Fairfield to Ontario (Oregon) | 477.33 mi (768.19 km) |
| Fairfield to Opa-locka (Florida) | 2,565.75 mi (4,129.18 km) |
| Fairfield to Opelika (Alabama) | 2,084.90 mi (3,355.33 km) |
| Fairfield to Opelousas (Louisiana) | 1,780.33 mi (2,865.16 km) |
| Fairfield to Orange (California) | 387.33 mi (623.35 km) |
| Fairfield to Orange (Texas) | 1,702.79 mi (2,740.37 km) |
| Fairfield to Orange City (Florida) | 2,410.87 mi (3,879.92 km) |
| Fairfield to Orangeburg (South Carolina) | 2,309.02 mi (3,716.01 km) |
