| Gaithersburg to Oswego (Illinois) | 610.65 mi (982.74 km) |
| Gaithersburg to Oswego (New York) | 300.56 mi (483.70 km) |
| Gaithersburg to Otsego (Minnesota) | 938.18 mi (1,509.86 km) |
| Gaithersburg to Ottawa (Illinois) | 630.84 mi (1,015.23 km) |
| Gaithersburg to Ottawa (Kansas) | 970.15 mi (1,561.31 km) |
| Gaithersburg to Ottumwa (Iowa) | 813.30 mi (1,308.87 km) |
| Gaithersburg to Overland (Missouri) | 707.28 mi (1,138.25 km) |
| Gaithersburg to Overland Park (Kansas) | 936.83 mi (1,507.69 km) |
| Gaithersburg to Overlea (Maryland) | 40.46 mi (65.11 km) |
| Gaithersburg to Oviedo (Florida) | 758.67 mi (1,220.96 km) |
| Gaithersburg to Owasso (Oklahoma) | 1,034.55 mi (1,664.95 km) |
| Gaithersburg to Owatonna (Minnesota) | 893.62 mi (1,438.14 km) |
| Gaithersburg to Owensboro (Kentucky) | 544.03 mi (875.54 km) |
| Gaithersburg to Owings Mills (Maryland) | 29.58 mi (47.61 km) |
| Gaithersburg to Owosso (Michigan) | 450.00 mi (724.20 km) |
