Concept:Govind Ballabh Pant Sagar is the reservoir formed by the Rihand Dam, and it lies in Uttar Pradesh.
Explanation:The Rihand Dam is built across the river Rihand.
The water stored behind this dam forms a large artificial lake.
This lake is named Govind Ballabh Pant Sagar.
It is situated in the Sonbhadra district of Uttar Pradesh.
It is the largest artificial lake in India.
Its spread also touches the border area of Madhya Pradesh and Uttar Pradesh.
Therefore, the lake is located in Uttar Pradesh.
Answer:Uttar Pradesh