Which River of India is known as Jamuna River in Bangladesh?

Concept: A large river that crosses an international boundary is very often recorded under a different local name on each side of that boundary. The same continuous channel therefore appears in two countries under two names, so a "what is this river called in that country" item is settled by tracing the channel itself across the border, never by matching similar-sounding names.

Application: Trace the channel that Bangladesh calls the Jamuna back upstream, step by step:

1. The stream rises on the Tibetan plateau as the Yarlung Tsangpo and runs east behind the main Himalayan range.

2. It turns south around the Namcha Barwa massif and enters India in Arunachal Pradesh as the Siang, also called the Dihang.

3. Joined by the Dibang and the Lohit near Sadiya, it takes the name Brahmaputra and flows south-west the length of the Assam valley.

4. Below Dhubri it crosses into Bangladesh, and there its main channel is called the Jamuna.

5. The Jamuna meets the Padma near Goalando; the combined river joins the Meghna and drains into the Bay of Bengal.

Cross-check: The same trace places the other rivers offered here:

• Ganga: inside Bangladesh its channel is called the Padma, and the Padma is the river the Jamuna flows into rather than the Jamuna itself.

• Narmada and Tapti: both are west-flowing peninsular rivers that end in the Gulf of Khambhat on the Arabian Sea, so neither river reaches Bangladesh at any point.

• Spelling trap: India’s Yamuna, the Ganga tributary that joins it at Prayagraj, is a wholly different river from the Jamuna of Bangladesh despite the near-identical name.

Result: The river of India known as the Jamuna in Bangladesh is the Brahmaputra.