| Owings Mills to Oskaloosa (Iowa) | 843.36 mi (1,357.26 km) |
| Owings Mills to Oswego (Illinois) | 625.63 mi (1,006.86 km) |
| Owings Mills to Oswego (New York) | 279.55 mi (449.89 km) |
| Owings Mills to Otsego (Minnesota) | 947.46 mi (1,524.78 km) |
| Owings Mills to Ottawa (Illinois) | 646.90 mi (1,041.09 km) |
| Owings Mills to Ottawa (Kansas) | 991.65 mi (1,595.91 km) |
| Owings Mills to Ottumwa (Iowa) | 830.82 mi (1,337.08 km) |
| Owings Mills to Overland (Missouri) | 729.48 mi (1,173.99 km) |
| Owings Mills to Overland Park (Kansas) | 958.00 mi (1,541.76 km) |
| Owings Mills to Overlea (Maryland) | 14.98 mi (24.11 km) |
| Owings Mills to Oviedo (Florida) | 784.18 mi (1,262.02 km) |
| Owings Mills to Owasso (Oklahoma) | 1,058.82 mi (1,704.01 km) |
| Owings Mills to Owatonna (Minnesota) | 905.05 mi (1,456.54 km) |
| Owings Mills to Owensboro (Kentucky) | 568.94 mi (915.62 km) |
| Owings Mills to Owosso (Michigan) | 456.56 mi (734.75 km) |
