| Castel Gandolfo to Oakley (California) | 6,222.90 mi (10,014.79 km) |
| Castel Gandolfo to Oakton (Virginia) | 4,509.07 mi (7,256.64 km) |
| Castel Gandolfo to Oakville (Missouri) | 5,083.13 mi (8,180.51 km) |
| Castel Gandolfo to Oatfield (Oregon) | 5,812.86 mi (9,354.90 km) |
| Castel Gandolfo to Ocala (Florida) | 5,135.81 mi (8,265.29 km) |
| Castel Gandolfo to Ocean Acres (New Jersey) | 4,342.15 mi (6,988.02 km) |
| Castel Gandolfo to Ocean City (New Jersey) | 4,374.50 mi (7,040.07 km) |
| Castel Gandolfo to Ocean Pines (Maryland) | 4,432.87 mi (7,134.02 km) |
| Castel Gandolfo to Ocean Pointe (Hawaii) | 8,039.04 mi (12,937.59 km) |
| Castel Gandolfo to Ocean Springs (Mississippi) | 5,383.18 mi (8,663.40 km) |
| Castel Gandolfo to Oceanside (California) | 6,361.02 mi (10,237.07 km) |
| Castel Gandolfo to Oceanside (New York) | 4,280.27 mi (6,888.42 km) |
| Castel Gandolfo to Ocoee (Florida) | 5,133.18 mi (8,261.06 km) |
| Castel Gandolfo to Oconomowoc (Wisconsin) | 4,804.42 mi (7,731.96 km) |
| Castel Gandolfo to Odenton (Maryland) | 4,475.23 mi (7,202.19 km) |
