| Grammichele to Olympia Heights (Florida) | 5,420.11 mi (8,722.83 km) |
| Grammichele to Omaha (Nebraska) | 5,472.20 mi (8,806.65 km) |
| Grammichele to On Top of the World Designated Place (Florida) | 5,379.52 mi (8,657.51 km) |
| Grammichele to Onalaska (Wisconsin) | 5,166.55 mi (8,314.76 km) |
| Grammichele to Oneida (New York) | 4,545.85 mi (7,315.83 km) |
| Grammichele to Oneonta (New York) | 4,540.38 mi (7,307.04 km) |
| Grammichele to Ontario (California) | 6,635.23 mi (10,678.38 km) |
| Grammichele to Ontario (Oregon) | 6,059.76 mi (9,752.24 km) |
| Grammichele to Opa-locka (Florida) | 5,408.78 mi (8,704.59 km) |
| Grammichele to Opelika (Alabama) | 5,381.56 mi (8,660.78 km) |
| Grammichele to Opelousas (Louisiana) | 5,782.63 mi (9,306.25 km) |
| Grammichele to Orange (California) | 6,655.66 mi (10,711.25 km) |
| Grammichele to Orange (Texas) | 5,877.02 mi (9,458.15 km) |
| Grammichele to Orange City (Florida) | 5,337.56 mi (8,589.97 km) |
| Grammichele to Orangeburg (South Carolina) | 5,135.88 mi (8,265.40 km) |
