It is one of the largest Upazilas of Bangladesh.
It is surrounded by Tripura (India) to the north, Hathazari and Kawkhali upazila (Rangamati District) to the south, Ramgarh, Manikchhari, Lakshmichhari, and Raozan upazilas on the east, Mirsharai and Sitakunda upazilas on the west.