| Frederick to Oswego (Illinois) | 593.61 mi (955.33 km) |
| Frederick to Oswego (New York) | 281.61 mi (453.20 km) |
| Frederick to Otsego (Minnesota) | 918.18 mi (1,477.66 km) |
| Frederick to Ottawa (Illinois) | 614.53 mi (988.98 km) |
| Frederick to Ottawa (Kansas) | 958.38 mi (1,542.36 km) |
| Frederick to Ottumwa (Iowa) | 798.06 mi (1,284.35 km) |
| Frederick to Overland (Missouri) | 696.24 mi (1,120.48 km) |
| Frederick to Overland Park (Kansas) | 924.73 mi (1,488.21 km) |
| Frederick to Overlea (Maryland) | 48.11 mi (77.43 km) |
| Frederick to Oviedo (Florida) | 775.02 mi (1,247.27 km) |
| Frederick to Owasso (Oklahoma) | 1,025.93 mi (1,651.08 km) |
| Frederick to Owatonna (Minnesota) | 874.61 mi (1,407.55 km) |
| Frederick to Owensboro (Kentucky) | 536.33 mi (863.15 km) |
| Frederick to Owings Mills (Maryland) | 33.28 mi (53.55 km) |
| Frederick to Owosso (Michigan) | 428.82 mi (690.12 km) |
