A tributary of the Sutlej, the Baspa river originates at a point near the tri-junction of Himachal Pradesh, Uttarakhand and Tibet. It flows due west for about 60 kilometers before joining the Sutlej at Kharcham. This is the Baspa valley.
A part of the Kinnaur district of Himachal Pradesh, the Baspa valley lies in the lap of the great Himalayas. Sangla is its largest town, and therefore the Baspa valley is sometimes also referred to as the Sangla valley.