The Kali Gandaki river source is at the border with Tibet at an elevation of 6,268 m (20,564 ft) at the Nhubine Himal Glacier in the Mustang region of Nepal.

The Kali Gandaki then flows southwest (with the name of Mustang Khola on old, outdated maps) through a sheer-sided, deep canyon before widening at the steel footbridge at Chele, where part of its flow funnels through a rock tunnel, and from this point the now wide river is called the Kali Gandaki on all maps.

Pandai river flows into Bihar from Nepal in the eastern end of the Valmiki Sanctuary and meets Masan.

[3] From its exit from the outermost Siwaliks foothills to the Ganga, the Gandak has built an immense megafan comprising Eastern Uttar Pradesh and North Western Bihar in the Middle Gangetic Plains.

[5] The important towns in the Indian part of the Gandak river are Valmikinagar (Bhainsalotan) - location of Gandak Barrage, Bagaha, Bettiah (district headquarters & field directorate of Valmiki Tiger Project), Harinagar (Ramnagar), Hajipur (across the Ganges 10  km from Patna) and Sonepur (also Known as Harihar Kshetra), near Patna.

Valmiki Sanctuary covers about 800 square kilometres (310 sq mi) of forest and was the 18th tiger reserve established in India.

Valmikinagar is located nearly 100 kilometres (62 mi) from Bettiah in the northernmost part of the West Champaran district, Bihar, bordering Nepal.

Valmikinagar is a small town with scattered habitation, mostly within the forest area and has a railroad station in the district of West Champaran, close to the railhead of Bagaha.

It has diverse landscapes, sheltering rich wildlife habitats and floral and faunal composition with the prime protected carnivores and was included in the National Conservation Programme of the Project Tiger in the year 1994.

Between the Dhaulagiri and Annapurna mountain ranges, the Gandaki River flows through the village of Muktinath and by the Ashram of Pulaha.

In ancient times, the mountain range surrounding Pulaha was called Salagiris due to the vast forests of sal trees.

Its massiveness and exquisite finish furnish striking proof of the skill and resources of the masons of Ashokan age.

Two more such pillars with their capitals removed have been discovered in Rampurwa village, close to Gandhi's Bhitiharawa Ashram in Gaunaha block.

[citation needed] The Bhitiharawa Ashram[10] of Mahatma Gandhi near Gaunaha in the eastern end of the Valmiki reserve.

The caves lie on the steep valley walls near the Kali Gandaki River in Upper Mustang.

Several groups of archaeologists and researchers have explored these stacked caves and found partially mummified human bodies and skeletons that are at least 2,000-3,000 years old.

Explorations of these caves by conservators and archaeologists have also led to the discovery of valuable religious paintings, sculptures, manuscripts and numerous artifacts belonging to the 12th to 14th century.

With Government of Nepal now according priority to private-sector participation in a multi-pronged approach, the pace of hydropower development will get accelerated.

[citation needed] The Gandak Project at Valmikinagar (Bhainsaloton) intercepts water of a catchment area of 37,410 km (23,250 mi), which is mostly in Nepal and partly in India.

Studies indicate that (a) it is feasible only in the lower reaches, (b) link it with India's number 1 highway from Allahabad to Haldia, and (c) cognizance has to be taken of the adverse situation which could arise due to increased irrigation use in dry seasons which could restrict the river level for maintaining possible navigation.

[citation needed] A part of episode 1 of the documentary series "The Living Planet" was filmed in the Kali Gandaki Gorge.