| Gaithersburg to Oakley (California) | 2,380.07 mi (3,830.36 km) |
| Gaithersburg to Oakton (Virginia) | 17.64 mi (28.39 km) |
| Gaithersburg to Oakville (Missouri) | 706.82 mi (1,137.52 km) |
| Gaithersburg to Oatfield (Oregon) | 2,328.47 mi (3,747.31 km) |
| Gaithersburg to Ocala (Florida) | 743.28 mi (1,196.20 km) |
| Gaithersburg to Ocean Acres (New Jersey) | 162.03 mi (260.75 km) |
| Gaithersburg to Ocean City (New Jersey) | 140.10 mi (225.48 km) |
| Gaithersburg to Ocean Pines (Maryland) | 122.68 mi (197.44 km) |
| Gaithersburg to Ocean Pointe (Hawaii) | 4,825.03 mi (7,765.14 km) |
| Gaithersburg to Ocean Springs (Mississippi) | 890.19 mi (1,432.62 km) |
| Gaithersburg to Oceanside (California) | 2,254.40 mi (3,628.11 km) |
| Gaithersburg to Oceanside (New York) | 216.02 mi (347.65 km) |
| Gaithersburg to Ocoee (Florida) | 769.98 mi (1,239.17 km) |
| Gaithersburg to Oconomowoc (Wisconsin) | 647.28 mi (1,041.69 km) |
| Gaithersburg to Odenton (Maryland) | 28.24 mi (45.45 km) |
