| Hermiston to Olympia Heights (Florida) | 2,550.60 mi (4,104.80 km) |
| Hermiston to Omaha (Nebraska) | 1,200.76 mi (1,932.43 km) |
| Hermiston to On Top of the World Designated Place (Florida) | 2,305.83 mi (3,710.87 km) |
| Hermiston to Onalaska (Wisconsin) | 1,374.52 mi (2,212.07 km) |
| Hermiston to Oneida (New York) | 2,133.00 mi (3,432.73 km) |
| Hermiston to Oneonta (New York) | 2,176.61 mi (3,502.92 km) |
| Hermiston to Ontario (California) | 819.63 mi (1,319.06 km) |
| Hermiston to Ontario (Oregon) | 168.34 mi (270.92 km) |
| Hermiston to Opa-locka (Florida) | 2,546.11 mi (4,097.57 km) |
| Hermiston to Opelika (Alabama) | 2,009.31 mi (3,233.68 km) |
| Hermiston to Opelousas (Louisiana) | 1,802.38 mi (2,900.65 km) |
| Hermiston to Orange (California) | 834.69 mi (1,343.30 km) |
| Hermiston to Orange (Texas) | 1,750.45 mi (2,817.08 km) |
| Hermiston to Orange City (Florida) | 2,359.50 mi (3,797.26 km) |
| Hermiston to Orangeburg (South Carolina) | 2,188.12 mi (3,521.45 km) |
