| Gaithersburg to Barberino di Mugello | 4,355.01 mi (7,008.71 km) |
| Gaithersburg to Barcellona-Pozzo di Gotto | 4,743.48 mi (7,633.89 km) |
| Gaithersburg to Bareggio | 4,209.33 mi (6,774.26 km) |
| Gaithersburg to Barga | 4,319.72 mi (6,951.91 km) |
| Gaithersburg to Bari | 4,702.90 mi (7,568.59 km) |
| Gaithersburg to Barletta | 4,670.30 mi (7,516.12 km) |
| Gaithersburg to Baronissi | 4,625.46 mi (7,443.95 km) |
| Gaithersburg to Barrafranca | 4,727.16 mi (7,607.63 km) |
| Gaithersburg to Bassano del Grappa | 4,316.50 mi (6,946.73 km) |
| Gaithersburg to Battipaglia | 4,639.67 mi (7,466.83 km) |
| Gaithersburg to Beinasco | 4,163.19 mi (6,700.01 km) |
| Gaithersburg to Bellinzago Novarese | 4,190.58 mi (6,744.09 km) |
| Gaithersburg to Belluno | 4,324.22 mi (6,959.16 km) |
| Gaithersburg to Belmonte Mezzagno | 4,663.95 mi (7,505.91 km) |
| Gaithersburg to Belpasso | 4,754.63 mi (7,651.84 km) |
