Historically, the bongo occurred in three disjunctive regions in eastern, central and western Africa but they now primarily occur from the dense, lowland forests of West Africa and Zaire to southern Sudan, with small and isolated populations in the forests of the highlands of Kenya and in the Congo.
The preferred habitat is disturbed mosaics in rainforests with fresh green vegetation, such as ground-level bushes and shrubs. In the mountainous forests of East Africa, however, they occur in dense bamboo and broad-leaved forests.
The bongo is the only forest antelope with a complex social system. In the bongo, this system includes breeding herds consisting of a few adult bulls and 6 to 50, but seldom more than 20, adult cows and young animals. Most of the adult bulls are solitary in habit, and nursery herds of calves are formed. The bongo is active by day and night with a peak of activity around midnight and again just before sunrise. It stays in the forest during the day and only comes into the open to visit salt licks at night. Bongos are inactive in the middle of the day and also stop feeding and move into shelter when it rains heavily. The range size of a breeding herd depends on the habitat quality and varies from 120 to 300 km2. In the mountainous regions of East Africa the bongo moves to the lower footslopes in the wet season.
A bull becomes sexually mature at around 30 months of age and a female at 27 months. Little is known about reproduction in the wild but mating seems to peak from April to November in someareas. A single calf weighing about 19,5 kg is born in a traditional calving ground after a gestation period of some 9 months. The calf remains hidden for the first few weeks of life