| Boulder to Blue Island (Illinois) | 923.73 mi (1,486.61 km) |
| Boulder to Blue Springs (Missouri) | 589.03 mi (947.95 km) |
| Boulder to Bluffdale (Utah) | 353.85 mi (569.46 km) |
| Boulder to Bluffton (Indiana) | 1,055.64 mi (1,698.88 km) |
| Boulder to Bluffton (South Carolina) | 1,454.90 mi (2,341.43 km) |
| Boulder to Blythe (California) | 680.56 mi (1,095.25 km) |
| Boulder to Blytheville (Arkansas) | 881.01 mi (1,417.85 km) |
| Boulder to Boca Raton (Florida) | 1,723.22 mi (2,773.25 km) |
| Boulder to Boerne (Texas) | 797.66 mi (1,283.72 km) |
| Boulder to Bogalusa (Louisiana) | 1,073.97 mi (1,728.38 km) |
| Boulder to Boiling Springs (South Carolina) | 1,316.56 mi (2,118.79 km) |
| Boulder to Boise (Idaho) | 616.34 mi (991.91 km) |
| Boulder to Bolingbrook (Illinois) | 902.07 mi (1,451.74 km) |
| Boulder to Bolivar (Missouri) | 658.13 mi (1,059.15 km) |
| Boulder to Bon Air (Virginia) | 1,495.08 mi (2,406.11 km) |
