| Preakness to Oskaloosa (Iowa) | 957.15 mi (1,540.39 km) |
| Preakness to Oswego (Illinois) | 733.43 mi (1,180.34 km) |
| Preakness to Oswego (New York) | 209.11 mi (336.53 km) |
| Preakness to Otsego (Minnesota) | 1,020.24 mi (1,641.92 km) |
| Preakness to Ottawa (Illinois) | 759.37 mi (1,222.09 km) |
| Preakness to Ottawa (Kansas) | 1,126.17 mi (1,812.39 km) |
| Preakness to Ottumwa (Iowa) | 947.35 mi (1,524.61 km) |
| Preakness to Overland (Missouri) | 869.37 mi (1,399.11 km) |
| Preakness to Overland Park (Kansas) | 1,091.13 mi (1,756.00 km) |
| Preakness to Overlea (Maryland) | 162.76 mi (261.94 km) |
| Preakness to Oviedo (Florida) | 935.13 mi (1,504.94 km) |
| Preakness to Owasso (Oklahoma) | 1,206.44 mi (1,941.58 km) |
| Preakness to Owatonna (Minnesota) | 989.81 mi (1,592.94 km) |
| Preakness to Owensboro (Kentucky) | 722.27 mi (1,162.39 km) |
| Preakness to Owings Mills (Maryland) | 171.72 mi (276.36 km) |
