Ajay River originates from the hills of Munger in Bihar. It flows through the Deoghar District in Jharkhand, joining with the Pathra and Jainti (Jayanti) rivers and proceeds on its journey through Dumka district to West Bengal. It flows down the plateau fringe, marking the boundary between Bankura and Birbhum districts in West Bengal where it meets the Bhagirathi river at Katwa in
Murshidabad.