Derai upazila on the north, Itna and Ajmiriganj upazilas on the south, Baniachang and Ajmiriganj upazilas on the east, Khaliajuri and Itna upazilas on the west.

Sullah thana was established in 1919 and was turned into an upazila in 1983. It consists of 4 union parishads, 68 mouzas, 114 villages.

Sullah 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.