Ghaghara River

The Karnali River, also known as the Ghaghara River in India, Mapcha Tsangpo in Tibet, and as the Sarayu River in the lower Ghaghara of India's Awadh, is a perennial trans-boundary river that originates in the northern slopes of the Himalayas in the Tibetan Plateau, cuts through the Himalayas in Nepal and joins the Sharda River at Brahmaghat in India. Together they form the Ghaghara River, a major left-bank tributary of the Ganges. With a length of , it is the longest river in Nepal. The total length of the Ghaghara up to its confluence with the Ganges at Revelganj in Bihar is . It is the largest tributary of the Ganges by volume and the second largest by length after Yamuna.

== Course == thumb|Source of Karnali River thumb| Ghaghara River in Ayodhya is also known as Saryu river thumb|Lake Manasarovar in [[Tibet near the source of the Karnali River]] The Karnali rises in the northern slopes of the Himalayas in Tibet, in the glaciers of Mapchachungo, at an elevation of about above sea level. The river flows south through one of the most remote and least explored areas of Nepal as the Karnali River. The Seti River drains the western part of the catchment and joins the Karnali in Doti District north of Dundras hill. Another tributary, the long Bheri, rises in the western part of Dhaulagiri Himalaya and drains the eastern part of the catchment, meeting the Karnali near Kuineghat in Surkhet.