Bishwamvarpur upazila and Meghalaya (India) on the north, Jagannathpur and Derai upazilas on the south, Dowarabazar and Chhatak upazilas on the east, Jamalganj and Bishwamvarpur upazilas on the west.

Sunamganj thana, now an upazila, was established in 1877. The upazila consists of one municipality, 17 union parishads, 265 mouzas and 424 villages.

Sunamganj Sadar Upazila is located in Sunamganj District. Upazilla(s)/Thana(s) in Sunamganj are Bishwamvarpur Upazila, Chhatak Upazila, Derai Upazila, Dharmapasha Upazila, Dowarabazar Upazila, Jagannathpur Upazila, Jamalganj Upazila, Sullah Upazila, Sunamganj Sadar Upazila, Tahirpur Upazila.