| Gaithersburg to Brown Deer (Wisconsin) | 624.92 mi (1,005.72 km) |
| Gaithersburg to Brownsburg (Indiana) | 491.16 mi (790.44 km) |
| Gaithersburg to Brownsville (Florida) | 936.46 mi (1,507.08 km) |
| Gaithersburg to Brownsville (Texas) | 1,481.82 mi (2,384.75 km) |
| Gaithersburg to Brownwood (Texas) | 1,324.04 mi (2,130.83 km) |
| Gaithersburg to Brunswick (Georgia) | 602.06 mi (968.92 km) |
| Gaithersburg to Brunswick (Ohio) | 283.51 mi (456.26 km) |
| Gaithersburg to Brushy Creek (Texas) | 1,303.53 mi (2,097.82 km) |
| Gaithersburg to Bryan (Texas) | 1,230.16 mi (1,979.76 km) |
| Gaithersburg to Bryant (Arkansas) | 898.93 mi (1,446.69 km) |
| Gaithersburg to Bryn Mawr-Skyway (Washington) | 2,301.64 mi (3,704.12 km) |
| Gaithersburg to Buckeye (Arizona) | 1,999.11 mi (3,217.26 km) |
| Gaithersburg to Buckhall (Virginia) | 31.05 mi (49.97 km) |
| Gaithersburg to Bucyrus (Ohio) | 325.98 mi (524.61 km) |
| Gaithersburg to Buda (Texas) | 1,325.57 mi (2,133.29 km) |
