Originating from the Kaimur hills, the river Karmanasha passes through Mirzapur district of U.P. and forms the western boundary of the district for about 170 Kms. The river Kudra, which forms eastern boundary separating Rohtas district, is a branch of the river Dhoba rising in Kaimur Plateau South-West of Tilauthu, and ultimately joins the river Karmanasha. The River Durgawati originates from Kaimur hills and flows in the northern direction. It is joined by the Kudra River before it merges finally into the river Karmanasha. The river Durgawati is perennial in nature and inundates a large area of land during heavy rains.