The district is situated in a vast floodplain, between the Kilombero River in the south-east and the Udzungwa-Mountains in the north-west. On the other side of the Kilombero River, in the south-east, the floodplain is part of Ulanga District. The district shares a portion of Udzungwa Mountains National Park with Kilolo District of Iringa.
According to the last census in 2002, the population of Kilombero District is 321,611 [2]
The main ethnic groups are Wapogoro, Wandamba, Wabena, and Wambunga and several others in small proportions.[3]
The area is predominantly rural with the semi-urban district headquarters Ifakara as major settlement.
The majority of the villagers are subsistence farmers of maize and rice. There are large plantations of teak wood in the Kilombero and the neighbouring Ulanga districts. In the north-west of the district, Illovo Sugar Company's sugar-cane plantations occupy most of the low lying area.[4][5][6]
^Corti, Graham, Fanning, Eibleis, Hinde, Roy, and Jenkins, Richard, 1999. A Conservation Assessment the Amphibian Communities of Miombo Woodland, Evergreen Forest and a Teak (I'ectona Grandis) Plantation in the Ulanga Valley, Tanzania (Technical Report 3). Frontier-Tanzania Savanna Research Programme, Dar es Salaaml
^Hinde, R., Corti, G., Fanning, E., & Jenkins, R., 1999a, A conservation assessment of large mammal use of miombo woodland, evergreen forest and a teak plantation in the Ulanga Valley, Tanzania, Frontier Tanzania Savanna Research Programme, Technical Report No. 2., unpublished, Frontier Tanzania, Dar es Salaam, Tanzania.
^Jenkins R., Roettcher, K, Corti, G & Fanning, E, 2000a, Large mammals and teak plantations in the Ulanga Valley, Annual Report, unpublished, Frontier Tanzania, Dar es Salaam, Tanzania.