| San Pietro in Casale to Olympia Heights (Florida) | 5,070.70 mi (8,160.51 km) |
| San Pietro in Casale to Omaha (Nebraska) | 4,997.04 mi (8,041.97 km) |
| San Pietro in Casale to On Top of the World Designated Place (Florida) | 5,003.00 mi (8,051.54 km) |
| San Pietro in Casale to Onalaska (Wisconsin) | 4,693.17 mi (7,552.93 km) |
| San Pietro in Casale to Oneida (New York) | 4,113.46 mi (6,619.98 km) |
| San Pietro in Casale to Oneonta (New York) | 4,112.97 mi (6,619.18 km) |
| San Pietro in Casale to Ontario (California) | 6,127.31 mi (9,860.95 km) |
| San Pietro in Casale to Ontario (Oregon) | 5,535.87 mi (8,909.12 km) |
| San Pietro in Casale to Opa-locka (Florida) | 5,058.70 mi (8,141.19 km) |
| San Pietro in Casale to Opelika (Alabama) | 4,974.84 mi (8,006.23 km) |
| San Pietro in Casale to Opelousas (Louisiana) | 5,362.50 mi (8,630.12 km) |
| San Pietro in Casale to Orange (California) | 6,147.69 mi (9,893.75 km) |
| San Pietro in Casale to Orange (Texas) | 5,452.72 mi (8,775.30 km) |
| San Pietro in Casale to Orange City (Florida) | 4,965.89 mi (7,991.82 km) |
| San Pietro in Casale to Orangeburg (South Carolina) | 4,740.52 mi (7,629.13 km) |
