In Bangladesh, the main distributary of the Ganges is called the Padma.
The Ganges reaches its first major bifurcation near the Farakka Barrage and the India–Bangladesh border. Its eastern and principal distributary then flows through Bangladesh under the name Padma. The river runs generally southeast before joining the Jamuna, Bangladesh’s name for the lower Brahmaputra, and later the Meghna.
The Padma is therefore not a separate unrelated river in this context. It is the name used for the Ganges’s main downstream branch in Bangladesh. River names in the delta can change at borders and confluences, which is why the same watercourse may be called the Ganges in India and the Padma farther east.
A common confusion is with the Meghna, which is a major river that joins the Padma downstream, or with the Jamuna, which joins it from the north. Together, these rivers form the immense Ganges–Brahmaputra–Meghna delta and discharge into the Bay of Bengal.