| Boulder to Buenaventura Lakes (Florida) | 1,579.33 mi (2,541.68 km) |
| Boulder to Buffalo (Minnesota) | 678.95 mi (1,092.66 km) |
| Boulder to Buffalo (New York) | 1,375.70 mi (2,213.98 km) |
| Boulder to Buffalo Grove (Illinois) | 910.78 mi (1,465.76 km) |
| Boulder to Buford (Georgia) | 1,237.47 mi (1,991.51 km) |
| Boulder to Bull Run (Virginia) | 1,477.10 mi (2,377.16 km) |
| Boulder to Bullhead City (Arizona) | 610.90 mi (983.14 km) |
| Boulder to Burbank (California) | 824.24 mi (1,326.49 km) |
| Boulder to Burbank (Illinois) | 919.37 mi (1,479.58 km) |
| Boulder to Burien (Washington) | 992.94 mi (1,597.98 km) |
| Boulder to Burkburnett (Texas) | 551.85 mi (888.11 km) |
| Boulder to Burke (Virginia) | 1,490.67 mi (2,399.01 km) |
| Boulder to Burke Centre (Virginia) | 1,488.56 mi (2,395.60 km) |
| Boulder to Burleson (Texas) | 680.29 mi (1,094.82 km) |
| Boulder to Burley (Idaho) | 475.93 mi (765.94 km) |
