Mount Kei Forest Reserve (formerly Mount Kei Rhino Sanctuary) is in the extreme north-west of Uganda. The northern boundaries are the Kaya river and the international border with Sudan; the Kechi river is to the east. The reserve can broadly be classified into dry Combretum-Terminalia savanna and Butyrospermum savanna woodland. There is only a sparse human population around the reserve, and it is largely undisturbed, but for small-scale human activities and some agricultural encroachment along the southern border. It is also important as a source of fuelwood, building poles, medicinal plants and honey, and serves as a water catchment area, which is one reason for its retention—it contains no tropical forest.

Mount Kei lies in the Sudan–Guinea Savanna biome, which is reflected in the species composition of the reserve. A total of 175 bird species is known. The reserve contains several species known in Uganda only from this area, including Accipiter brevipes, Buteo auguralis, Merops orientalis, Euschistospiza dybowskii and Nectarinia osea.

There are also more than 30 uncommon plant species in the reserve, three of them known in Uganda from this reserve only, i.e. Aeschynomene schimperi, Combretum racemosum and Morinda titanopylla. A shrew, Crocidura somalica, is known from no other site in Uganda.