The Kali Gandaki Gorge or Andha Galchi is the Gandaki River gorge in the Himalayas in the Nepal. Depth of throat is difficult to define because of a disagreement over the height of the rim, but by some measures of the Kali Gandaki is deep throat in the world.
The upper part of the gorge is also called Thak Khola after the Thakali people who became successful Himalayan trade. Geologically, it is a néogènes graben.
Gorge separates the major peaks of the Dhaulagiri (8 167 m/26 795 ft) to the West and Annapurna (8 091 m/26 545 ft) to the East. If the measurement of the depth of a canyon by the difference between the height of the river and the heights of the peaks on either side, the gorge is the deepest in the world.
The portion of the River directly between the Dhaulagiri and Annapurna (7 km downstream the Tukuche) is at an altitude of 2520 metres, 5571 metres lower than Annapurna I. The River is older than the Himalayas. Tectonic activity forced the higher mountains, the river has cut through the uprising. This region is known for fossils shaligram, revered as one of the five forms of non-living of the Lord Vishnu.
The source of the River Kali Gandaki coincides with the Tibetan border and the fracture of basin Ganges-Brahmaputra. The River then flows through the ancient Kingdom of Mustang. It flows in a canyon sheer-sided, deep, immediately to the South of the capital of the Mustang of Lo Manthang, then widens as approach of Kagbeni, Mustang where high Himalayan ranges begin to close. The river continues to the South, Jomsom, Marpha and Tukuche to the deepest part of the throat, 7 km south of Tukuche the area of Lete. The gorge then broadens past Dana and Tatopani towards Beni.
The Kali Gandaki gorge has been used as a trade route between the India and Tibet for centuries. Today, it is part of a route from Pokhara to Muktinath, part hiking the Annapurna Circuit. The gorge is in the area of Conservation of Annapurna.