Kishoreganj and Habiganj district on the north, Comilla district on the south, Hobiganj district and Tripura State of India on the east and meghna river, Kishoreganj, Narsingdi and Narayanganj districts on the west.

Brahmanbaria district, which was included in Comilla district (formerly Tipera district) was established in 1984. Before 1830 the Sarail Pargana was a part of Mymensingh district. The district has 4 municipalities, 39 wards, 97 mahallas, 7 upazilas, one thana, 98 union parishads, 1052 mouzas and 1329 villages. The upazilas are banchharampur, kasba, nabinagar, nasirnagar, brahmanbaria sadar, sarail and akhaura.

Akhaura Upazila, Bancharampur Upazila, Brahmanbaria Sadar Upazila, Kasba Upazila, Nabinagar Upazila, Nasirnagar Upazila, Sarail Upazila