Bhutan:
about half the size of Indiana

Bolivia:
slightly less than three times the size of Montana

Bosnia and Herzegovina:
slightly smaller than West Virginia

Botswana:
slightly smaller than Texas

Bouvet Island:
about 0.3 times the size of Washington, DC

Brazil:
slightly smaller than the US

British Indian Ocean Territory:
about 0.3 times the size of
Washington, DC

British Virgin Islands:
about 0.9 times the size of Washington, DC

Brunei:
slightly smaller than Delaware

Bulgaria:
slightly larger than Tennessee