Nabinagar is an upazila of Brahmanbaria District in the Division of Chattogram, Bangladesh. Nabinagar Thana was turned into an upazila in 1983.

Brahmanbaria is a district in eastern Bangladesh located in the Chittagong Division. Geographically, it is mostly farmland and is topographically part of the Gangetic Plain. It is bounded by the districts of Kishoreganj and Habiganj to the north, Narsingdi District and Narayanganj to the west, Comilla to the south, and the Indian state of Tripura to the east. It was a part of Comilla District until 15 February 1984.