The 17-year-old girl was involved in an affair with 35-year-old Santosh, a father of two from Guthari village under Didarganj police station, they said.
With the family members of the two being opposed to their relationship, the duo eloped from their houses yesterday afternoon and were found near a village canal in the evening.
The two were rushed to a hospital in Jaunpur district, where the girl died, while Santosh remains in a critical condition, they said.