| Castel Gandolfo to Odessa (Texas) | 5,885.69 mi (9,472.11 km) |
| Castel Gandolfo to Ogden (Utah) | 5,742.08 mi (9,240.99 km) |
| Castel Gandolfo to Oildale (California) | 6,290.83 mi (10,124.11 km) |
| Castel Gandolfo to Ojus (Florida) | 5,183.25 mi (8,341.64 km) |
| Castel Gandolfo to Okemos (Michigan) | 4,657.48 mi (7,495.49 km) |
| Castel Gandolfo to Oklahoma City (Oklahoma) | 5,514.50 mi (8,874.73 km) |
| Castel Gandolfo to Okmulgee (Oklahoma) | 5,446.81 mi (8,765.79 km) |
| Castel Gandolfo to Olathe (Kansas) | 5,244.24 mi (8,439.79 km) |
| Castel Gandolfo to Old Jamestown (Missouri) | 5,064.07 mi (8,149.83 km) |
| Castel Gandolfo to Oldsmar (Florida) | 5,209.74 mi (8,384.27 km) |
| Castel Gandolfo to Olean (New York) | 4,433.44 mi (7,134.93 km) |
| Castel Gandolfo to Olive Branch (Mississippi) | 5,221.33 mi (8,402.92 km) |
| Castel Gandolfo to Olivehurst (California) | 6,155.43 mi (9,906.21 km) |
| Castel Gandolfo to Olney (Maryland) | 4,488.77 mi (7,223.98 km) |
| Castel Gandolfo to Olympia (Washington) | 5,724.83 mi (9,213.22 km) |
