| Round Rock to Blue Island (Illinois) | 948.32 mi (1,526.18 km) |
| Round Rock to Blue Springs (Missouri) | 616.95 mi (992.88 km) |
| Round Rock to Bluffdale (Utah) | 1,054.42 mi (1,696.92 km) |
| Round Rock to Bluffton (Indiana) | 993.09 mi (1,598.22 km) |
| Round Rock to Bluffton (South Carolina) | 992.94 mi (1,597.98 km) |
| Round Rock to Blythe (California) | 1,014.19 mi (1,632.18 km) |
| Round Rock to Blytheville (Arkansas) | 583.21 mi (938.59 km) |
| Round Rock to Boca Raton (Florida) | 1,103.07 mi (1,775.22 km) |
| Round Rock to Boerne (Texas) | 81.72 mi (131.52 km) |
| Round Rock to Bogalusa (Louisiana) | 463.91 mi (746.59 km) |
| Round Rock to Boiling Springs (South Carolina) | 961.86 mi (1,547.96 km) |
| Round Rock to Boise (Idaho) | 1,359.44 mi (2,187.81 km) |
| Round Rock to Bolingbrook (Illinois) | 936.60 mi (1,507.32 km) |
| Round Rock to Bolivar (Missouri) | 546.00 mi (878.70 km) |
| Round Rock to Bon Air (Virginia) | 1,244.64 mi (2,003.06 km) |
