Betsiboka River is a long river in central-north
Madagascar. It flows northwestward and empties to
Bombetoka Bay, forming a large
delta. It originates to the east of
Antananarivo. The river is surrounded in
mangroves. The river is distinct for its red-coloured water, which is caused by river sediments. The river carries an enormous amount of reddish-orange silt to the sea. Much of this silt is deposited at the mouth of the river or in the bay.