Sutlej

The longest river in Himachal Pradesh and the spine of its power economy. It is the only one of the five that rises outside India — from Rakas Tal beside Mansarovar in Tibet — and it enters the country through Shipki La in Kinnaur, which makes that pass a double answer: a trade route and a river gate.

Two junctions are regularly asked. The Spiti joins at Khab, and the Baspa joins at Karchham — both in Kinnaur, both within about forty kilometres of each other.