Mikumi National Park was gazetted in 1964, with extensions to the north and south added in 1975. It is found in the region of Morogorocovering an Area of 323,000 hactares at an Altitude of 500 to 1,250 meters. Mikumi occupies a lowland area between several mountain chains. It is surrounded by the Rubeho mountains to the north-west, the Ukaguru mountains to the north, the Uluguru mountains to the north-east, the Udzungwa mountains to the south-west, with the Uvidunda Mountains to the west.

The main feature of Mikumi National Park is the flood-plain of the Mkata river, with its swamps and pools, which flows north through the park, draining mountains to the west. The main road linking Dar-es-Salaam and Zambia passes through the park, skirting the flood-plain to the north and a range of low hills to the south. These hills are covered with miombo woodland with extensive areas of riverine forest, characteristic of the coastal lowlands in the valleys. To the south these hills rise to 1,250 m at Mount Malundwe, covered by montane forest, and further south they border the Selous Game Reserve.

Some 393 bird species are known to occur in the area. Falco naumanni is a regular passage migrant in March and April, but there have been no records of large flocks or wintering birds. There are few records of Crexcrex, but the flood-plain offers much suitable habitat for passage birds on their northward journey. Ardeolaidae has been rarely recorded from the few permanent ponds. There are a few passage records of Circus macrourus and one of Acrocephalusgriseldis from just outside the park; much suitable habitat exists within it.

Dendropicosstierlingi is an uncommon bird in the west of the Selous, to the south of Mikumi, and may occur in the south of the park. Circaetusfasciolatus it is expected to occur in riverine forest. Two species of the Afrotropical Highlands, three of the Somali - Masai and five of the East African Coast biomes all occur. Mikumi is one of few areas where nominally allopatric members of a superspecies clearly overlap. Henceforth both Tockuspallidirostris and Tockusnasutus are common and Falco ardosiaceus occurs alongside the commoner Falco dickinsoni. The riverine forest holds Anthreptesneglectus, Ploceus bicolor and Dicrurusludwigii and probably contains many other species more typical of coastal forest. A population of the uncommon Jynxruficollis is known from woodland along the park boundary.