The region occupies 16,720 sq. kms or 1.9% of Tanzania Mainland land area of 885,987 sq. kms. It is the second smallest region after Kilimanjaro.
Mtwara region is administratively subdivided into 5 districts, 21 divisions, 98 wards and 554 villages. smallest of the districts is logically the urban district of Mtwara/Mikindani at 163 sq. kms. and the largest is Masasi at 8,940 sq. kms which is 55 times the size of the urban district.