The village of Lachung is perched on the craggy bank of the river approximately 23 kilometres (14 mi) from Chungthang.

It is at Chungthang where the Lachung and Lachen rivers converge and give rise to the Teesta.

After this point the river flows to Dikchu through a deep ravine and drops to a height of 550 metres (1,800 ft).

In lachung town, there's banned package drinking water and total restrictions for usage.

The crystal clear lachung water is used for drinking Amitabh Bachchan Falls (real name is Bhewma Falls; 27°38′02″N 88°42′15″E / 27.63381°N 88.70406°E / 27.63381; 88.70406) lies on the road connecting Chungthang to Yumthang Valley in Lachung, North Sikkim district of Sikkim.