| Birkenhead to Olympia Heights (Florida) | 4,297.99 mi (6,916.95 km) |
| Birkenhead to Omaha (Nebraska) | 4,119.69 mi (6,630.00 km) |
| Birkenhead to On Top of the World Designated Place (Florida) | 4,202.71 mi (6,763.60 km) |
| Birkenhead to Onalaska (Wisconsin) | 3,817.13 mi (6,143.07 km) |
| Birkenhead to Oneida (New York) | 3,268.09 mi (5,259.49 km) |
| Birkenhead to Oneonta (New York) | 3,272.01 mi (5,265.78 km) |
| Birkenhead to Ontario (California) | 5,243.83 mi (8,439.12 km) |
| Birkenhead to Ontario (Oregon) | 4,659.20 mi (7,498.25 km) |
| Birkenhead to Opa-locka (Florida) | 4,285.42 mi (6,896.72 km) |
| Birkenhead to Opelika (Alabama) | 4,145.89 mi (6,672.16 km) |
| Birkenhead to Opelousas (Louisiana) | 4,519.55 mi (7,273.51 km) |
| Birkenhead to Orange (California) | 5,264.22 mi (8,471.95 km) |
| Birkenhead to Orange (Texas) | 4,605.97 mi (7,412.60 km) |
| Birkenhead to Orange City (Florida) | 4,170.96 mi (6,712.51 km) |
| Birkenhead to Orangeburg (South Carolina) | 3,924.22 mi (6,315.42 km) |
