Islampur is not categorized as a city; politically and demographically it lies between a town and a village, and is therefore called a notified area.

As of 2011[update] India census,[4] Islampur is a Nagar Parishad city in district of Nalanda, Bihar.

The Islampur Nagar Parishad has population of 43,211 of which 18,356 are males while 17,285 are females as per report released by Census India 2011.

Islampur Nagar Parishad has total administration over 6,088 houses to which it supplies basic amenities like water and sewerage.

It is also authorized to build roads within Nagar Parishad limits and impose taxes on properties coming under its jurisdiction.

Moharram is the most popular Muslim festival.One of the Famous Urs of Hazrat Data Lodi Shah Diwan RA was celebrated on 19 & 20 (Hijri date) as 2 days in the Month of Muharram.