Patharghata and Barguna Sadar upazilas on the south, bishkhali river and Betagi upazila on the east, Mathbaria upazila on the west and Kathalia upazila on the north.

Bamna thana was established in 1968 and was turned into an upazila in 1983. The upazila consists of 4 union parishads, 39 mouzas and 49 villages.

Bamna Upazila is located in Barguna District. Upazilla(s)/Thana(s) in Barguna are Amtali Upazila, Bamna Upazila, Barguna Sadar Upazila, Betagi Upazila, Patharghata Upazila.

Remnants of the boundary walls of the estate of a local zamindar of early 18th century.