| San Gregorio di Catania to Olympia Heights (Florida) | 5,434.46 mi (8,745.92 km) |
| San Gregorio di Catania to Omaha (Nebraska) | 5,474.03 mi (8,809.60 km) |
| San Gregorio di Catania to On Top of the World Designated Place (Florida) | 5,391.64 mi (8,677.01 km) |
| San Gregorio di Catania to Onalaska (Wisconsin) | 5,168.53 mi (8,317.95 km) |
| San Gregorio di Catania to Oneida (New York) | 4,552.38 mi (7,326.34 km) |
| San Gregorio di Catania to Oneonta (New York) | 4,547.42 mi (7,318.37 km) |
| San Gregorio di Catania to Ontario (California) | 6,632.25 mi (10,673.57 km) |
| San Gregorio di Catania to Ontario (Oregon) | 6,053.36 mi (9,741.94 km) |
| San Gregorio di Catania to Opa-locka (Florida) | 5,423.07 mi (8,727.58 km) |
| San Gregorio di Catania to Opelika (Alabama) | 5,390.97 mi (8,675.92 km) |
| San Gregorio di Catania to Opelousas (Louisiana) | 5,790.88 mi (9,319.52 km) |
| San Gregorio di Catania to Orange (California) | 6,652.67 mi (10,706.44 km) |
| San Gregorio di Catania to Orange (Texas) | 5,884.88 mi (9,470.79 km) |
| San Gregorio di Catania to Orange City (Florida) | 5,350.06 mi (8,610.10 km) |
| San Gregorio di Catania to Orangeburg (South Carolina) | 5,146.24 mi (8,282.07 km) |
