Tons River, in Uttaranchal, is an important tributary of the Yamuna River. It has two feeder streams - Supin and Rupin rivers. These two rivers merge near
Naitwar and the channel downstream is known as Tons River. It flows along the 'V'-shaped Tons Valley, before merging with Yamuna at Kalsi, around 50 km from Dehradun. The famous Duryodhan Temple in Jakhol is located on the banks of Tons River.
