| Comacchio to Olympia Heights (Florida) | 5,106.80 mi (8,218.59 km) |
| Comacchio to Omaha (Nebraska) | 5,025.90 mi (8,088.41 km) |
| Comacchio to On Top of the World Designated Place (Florida) | 5,038.12 mi (8,108.07 km) |
| Comacchio to Onalaska (Wisconsin) | 4,722.28 mi (7,599.77 km) |
| Comacchio to Oneida (New York) | 4,145.95 mi (6,672.26 km) |
| Comacchio to Oneonta (New York) | 4,145.77 mi (6,671.97 km) |
| Comacchio to Ontario (California) | 6,151.94 mi (9,900.60 km) |
| Comacchio to Ontario (Oregon) | 5,557.75 mi (8,944.33 km) |
| Comacchio to Opa-locka (Florida) | 5,094.77 mi (8,199.25 km) |
| Comacchio to Opelika (Alabama) | 5,008.58 mi (8,060.53 km) |
| Comacchio to Opelousas (Louisiana) | 5,395.41 mi (8,683.08 km) |
| Comacchio to Orange (California) | 6,172.32 mi (9,933.39 km) |
| Comacchio to Orange (Texas) | 5,485.36 mi (8,827.83 km) |
| Comacchio to Orange City (Florida) | 5,001.21 mi (8,048.67 km) |
| Comacchio to Orangeburg (South Carolina) | 4,774.88 mi (7,684.43 km) |
