Sher Singh (54), Verendra Singh (22), Channa Devi (44) and Triloka Devi (52), all residents of Kaneri village, were coming from Delhi to attend a religious festival in Masi, when their car fell from 20 feet into a local river, they said.
The driver and another family member sustained severe injuries and have been taken to a hospital in Haldwani, police said.
Further investigation is on into the incident, police said.