Ajay is a river in India. It originates from Munger District of Bihar. This river irrigates Northern and Eastern parts of Deoghar District and meets Bhagirathi river at Murshidabad (in West Bengal). A Barrage has been built over this River. During summer, narrow strip of water flows. Rivulets like Dadhwa, Patro, Jayanti and Kendua merge with Ajay at different places.