| Castle Rock to Blue Island (Illinois) | 914.06 mi (1,471.04 km) |
| Castle Rock to Blue Springs (Missouri) | 566.84 mi (912.25 km) |
| Castle Rock to Bluffdale (Utah) | 382.86 mi (616.16 km) |
| Castle Rock to Bluffton (Indiana) | 1,042.82 mi (1,678.26 km) |
| Castle Rock to Bluffton (South Carolina) | 1,423.81 mi (2,291.40 km) |
| Castle Rock to Blythe (California) | 671.86 mi (1,081.25 km) |
| Castle Rock to Blytheville (Arkansas) | 850.47 mi (1,368.69 km) |
| Castle Rock to Boca Raton (Florida) | 1,685.00 mi (2,711.75 km) |
| Castle Rock to Boerne (Texas) | 748.23 mi (1,204.15 km) |
| Castle Rock to Bogalusa (Louisiana) | 1,032.66 mi (1,661.91 km) |
| Castle Rock to Boiling Springs (South Carolina) | 1,290.06 mi (2,076.15 km) |
| Castle Rock to Boise (Idaho) | 656.44 mi (1,056.43 km) |
| Castle Rock to Bolingbrook (Illinois) | 892.58 mi (1,436.47 km) |
| Castle Rock to Bolivar (Missouri) | 629.97 mi (1,013.85 km) |
| Castle Rock to Bon Air (Virginia) | 1,476.24 mi (2,375.79 km) |
