Brahmaputra
brick brim broth brat brake brawl.............. oh and br br br br br
Brook
Brain, breast and bronchi are body parts. They begin with the letters BR.
The opposite of "narrow" that starts with the letters "Br" is "broad." "Broad" refers to something that is wide or large in extent, contrasting with the limited width implied by "narrow."
brunt
It could be brio, bred, brag, brew, brie...
Phillip Rivers
No rivers starting with 'U'
the great animas
Ganges
OriginOutpour
Brisling: small herring processed like a sardine