| Preakness to Olympia (Washington) | 2,415.90 mi (3,888.02 km) |
| Preakness to Olympia Heights (Florida) | 1,108.10 mi (1,783.32 km) |
| Preakness to Omaha (Nebraska) | 1,133.75 mi (1,824.60 km) |
| Preakness to On Top of the World Designated Place (Florida) | 935.17 mi (1,505.00 km) |
| Preakness to Onalaska (Wisconsin) | 888.26 mi (1,429.52 km) |
| Preakness to Oneida (New York) | 165.18 mi (265.83 km) |
| Preakness to Oneonta (New York) | 113.46 mi (182.60 km) |
| Preakness to Ontario (California) | 2,400.38 mi (3,863.04 km) |
| Preakness to Ontario (Oregon) | 2,164.36 mi (3,483.20 km) |
| Preakness to Opa-locka (Florida) | 1,094.97 mi (1,762.19 km) |
| Preakness to Opelika (Alabama) | 839.98 mi (1,351.82 km) |
| Preakness to Opelousas (Louisiana) | 1,229.20 mi (1,978.20 km) |
| Preakness to Orange (California) | 2,418.38 mi (3,892.01 km) |
| Preakness to Orange (Texas) | 1,323.67 mi (2,130.24 km) |
| Preakness to Orange City (Florida) | 920.00 mi (1,480.60 km) |
