There were around 50 people in the boat when the accident took place late Sunday near Behrampur village, around 25 km from here. Nearly 30 people were still missing, a police official said.
According to police, all of them were going to a fair to mark the end of Durga puja.
"It appears the accident took place because of overloading," the police official said.
Search and rescue operations are on.
The Bihar government has ordered a probe into the accident and announced compensation of Rs.1 lakh each for the kin of the dead.
Deccan Herald is on WhatsApp Channels| Join now for Breaking News & Editor's Picks