| Gaithersburg to Blue Island (Illinois) | 577.32 mi (929.10 km) |
| Gaithersburg to Blue Springs (Missouri) | 913.73 mi (1,470.51 km) |
| Gaithersburg to Bluffdale (Utah) | 1,833.61 mi (2,950.91 km) |
| Gaithersburg to Bluffton (Indiana) | 435.90 mi (701.51 km) |
| Gaithersburg to Bluffton (South Carolina) | 521.63 mi (839.48 km) |
| Gaithersburg to Blythe (California) | 2,100.21 mi (3,379.96 km) |
| Gaithersburg to Blytheville (Arkansas) | 729.02 mi (1,173.24 km) |
| Gaithersburg to Boca Raton (Florida) | 897.35 mi (1,444.14 km) |
| Gaithersburg to Boerne (Texas) | 1,380.59 mi (2,221.85 km) |
| Gaithersburg to Bogalusa (Louisiana) | 918.33 mi (1,477.91 km) |
| Gaithersburg to Boiling Springs (South Carolina) | 385.63 mi (620.62 km) |
| Gaithersburg to Boise (Idaho) | 2,027.62 mi (3,263.14 km) |
| Gaithersburg to Bolingbrook (Illinois) | 598.95 mi (963.91 km) |
| Gaithersburg to Bolivar (Missouri) | 882.93 mi (1,420.94 km) |
| Gaithersburg to Bon Air (Virginia) | 113.32 mi (182.38 km) |
