In Assam it drains the districts of Karbi Anglong, Dima Hasao, Kamrup and Nagaon.

It is noted for several spectacular waterfalls along its course which has several deep gorges and rapids in the 120 kilometres (75 mi) of its flow before debouching into the plains at Nagaon district.

[4] The Kopili Hydro Electric Project, located across the districts of Dima Hasao in Assam and Jaintia Hills in Meghalaya and run by the North Eastern Electric Power Corporation, consists of the Khandong and Umrongso dams and their reservoirs and three power houses that have a total installed capacity of 275 MW.

[2] Unscientific opencast coal mining in the Kopili's upper reaches in Meghalaya has led to acidification of the river which has in turn left part of the river's course biologically dead, making the water unfit for human consumption and has led to frequent outages at the Kopili Hydro Electric Project's power stations.

The penstock pipe that takes water from the Umrangso dam to the hydropower house burst during early hours in Assam’s Dima Hasao district, and massive quantity of water erupted, a lot of it entered the power house, where four employees of NEEPCO were feared to have been trapped/ washed away.