The park was established in 1935 during the French Colonial period but was extended in 2001, in consultation with the local communities, to its current expanse. Odzala-Kokoua is one of three signature areas of the 191,541km2 trans-boundary mosaic known as the Tridom project. Declared a UNESCO Man and Biosphere Reserve in 1977 and nominated in 2008 to become a UNESCO World Heritage Site, Odzala as a conservation priority is unattested. Odzala is also recognised as an Important Bird Area by Birdlife International. African Parks took over the management of Odzala-Kokoua in November 2010 under the terms of a partnership agreement with the Government of the Republic of Congo. This agreement provides for the creation of a dedicated non-profit entity, the Odzala Foundation, which will have overall jurisdiction over the park.
Odzala-Kokoua is a ‘frontier forest' which harbours some of the last extensive blocks of contiguous forest ecosystems that are capable of supporting viable populations of large mammals. The southern part of the park is predominantly a savannah-forest mosaic and forest gallery ecosystem. The centre of the park is dominated by Marantaceae Forest where a high density of gorilla and elephant are found. Further north, the park is covered by mature rain forest.
One of the unique aspects of this park is its numerous clearings, called ‘bais', that provide an opportunity to observe the forest wildlife easily where it is normally difficult to see through the dense vegetation in a tropical forest. The majestic Mambili River provides one of the few access routes to the park. The Ekoutou escarpment (80km) with its lichen forest, and Djoua swamp in the north west of the park remain some of the most remote areas in which only a few scientific expeditions have been conducted.
The biological diversity is exceptional, including more than 400 bird species, 114 mammal species and in excess of 4,400 varieties of plants. Of the 16 primate species, it is the gorilla and chimpanzee populations on which OKNP's reputation rests. Odzala also boasts numerous herbivore species. These include elephants, numbering in the thousands, and a few populations of hippopotamus.
The pressure on the fauna by the local populations (around 10,000 people living in approximately 70 villages along the periphery of the park) is considerable as hunting represents a critical source of revenue and protein for the local people. The major threats include commercial and subsistence hunting for bushmeat, elephant poaching for ivory and the construction of roads on the periphery of the park, which exacerbates the problem of poaching as it provides easy access to previously isolated forest. Diseases such as ebola also threaten in particular the great ape populations.