There were 11 persons aboard the boat and only one of them, a girl, could be saved, District Magistrate Upendra Kumar told PTI of the mishap that occurred at around 10.30 P.M. last night.
Among the dead are five girls and four boys, all aged between 8 to 12 years, Kumar said. As tragedy struck, the screams of the victims brought villagers nearby to their rescue.
While nine of the victims drowned before the rescuers could reach them, a girl who was admitted to a local hospital in a serious condition died this morning, the DM added.
The victims, who belong to two families, were being ferried back home to Khawan village from Pandit Basa village on the other side of the river where they had gone to attend a function at the home of a district JD(U) leader, Mohan Sharma.
The accident took place in Alamnagar block in the Ratwara police outpost area. Kosi and other rivers have been in spate since the onset of monsoon.
Last night's incident is being attributed to a rise in the water level in the tributary river. Madhepura is the Parliamentary constituency of JD(U) national president Sharad Yadav.