| Campbell to Olympia Heights (Florida) | 2,555.25 mi (4,112.28 km) |
| Campbell to Omaha (Nebraska) | 1,406.97 mi (2,264.29 km) |
| Campbell to On Top of the World Designated Place (Florida) | 2,343.92 mi (3,772.18 km) |
| Campbell to Onalaska (Wisconsin) | 1,665.94 mi (2,681.07 km) |
| Campbell to Oneida (New York) | 2,444.80 mi (3,934.52 km) |
| Campbell to Oneonta (New York) | 2,480.18 mi (3,991.46 km) |
| Campbell to Ontario (California) | 331.14 mi (532.93 km) |
| Campbell to Ontario (Oregon) | 533.90 mi (859.23 km) |
| Campbell to Opa-locka (Florida) | 2,554.05 mi (4,110.34 km) |
| Campbell to Opelika (Alabama) | 2,082.27 mi (3,351.09 km) |
| Campbell to Opelousas (Louisiana) | 1,767.31 mi (2,844.21 km) |
| Campbell to Orange (California) | 334.08 mi (537.66 km) |
| Campbell to Orange (Texas) | 1,687.11 mi (2,715.13 km) |
| Campbell to Orange City (Florida) | 2,403.70 mi (3,868.38 km) |
| Campbell to Orangeburg (South Carolina) | 2,311.01 mi (3,719.21 km) |
