The Kopai River is a tributary of the Mayurakshi River. It flows past such towns as Santiniketan, Bolpur, Kankalitala, Kirnahar and Labhpur in Birbhum district in the Indian state of West Bengal. It is a small river in dry season but overflows its banks during the monsoon.Literary associationThe area around the river quite often has red soil, which forms ravines on the river bank with weathering and is popular as the khoai. It has inspired literary figures in the area. It is described by Rabindranath Tagore as follows - amader chhoto nodi chale anke bankeyboisakh masey taar hantu jal thakeyOur small stream moves forward in bends and curvesIn the month of Baisakh it only has knee deep waters The local name of a sickle-shaped curve in the river inspired the title of the novel Hansuli Banker Upakatha (Story of the Sickle-shaped Curve) by Tarasankar Bandyopadhyay, made into a film by Tapan Sinha.ArchaeologyMicroliths of crystalline stone and petrified wood from about 1250–1000 BC are found in many places in the Ajay-Kunur-Kopai river system.