Mohanpur Istamrar is a village in Rupauli tehsil in district of Purnia, Bihar, India. As per the data provided by Census of India in 2011, total population of Mohanpur Istamrar was 10,692 which includes 5,555 males and 5,137 females. Mohanpur Istamrar covers 656 ha area. Pincode of Mohanpur Istamrar is 853204.