The incident occurred this morning when the boat ferrying 17 persons capsized midstream, District Magistrate Shambhu Nath said.
Kamlesh (30), her daughter Ashiqa (2), Neksi (50) and Chandrawati (40) were killed, he said, adding, their bodies have been fished out.
The DM said that five others were missing and efforts were being made to trace them with the help of divers.
The bodies have been sent for post-mortem.