Odzala-Kokoua is an approximately 13,500-square-kilometre (5,200 sq mi) national park and biosphere reserve in northwestern Republic of the Congo, established in 1935.

[1][3][4] The park has preserved old-growth rainforest and variable terrain, ranging from 350-metre (1,150 ft) tall hills to dense jungle and numerous glades.

[1][5] Odzala-Kokoua is one of Africa's oldest national parks, first protected in 1935 and given official designation by presidential decree from Denis Sassou Nguesso in 2001.

Wilderness Safaris invested in the park by improving infrastructure, constructing two luxury lodges, and providing additional training to guides and rangers.

[3][6][18] In 2005, Ebola killed approximately 5,000 gorillas within a 1,042 sq mi (2,700 km2) area of the park, according to the United States Fish and Wildlife Service.

[2] The number of gorillas in Odzala-Kokoua has since increased, following efforts by conservation organizations and at least one tourism company to preserve and rehabilitate the park.

[3] A survey of diurnal primates, conducted during the mid 1990s, showed significant monkey populations in Republic of the Congo's forest region.

[19] Odzala-Kokoua had the highest densities of western lowland gorilla and chimpanzee in Central Africa recorded to date.

[19] The results of a survey conducted in clearings within the northern part of the park, published in 1998, showed the presence of thirteen large mammals, the most frequent of which were the bongo, buffalo, African elephant, forest hog, giant forest hog, gorilla, and sitatunga.

[21] Survey results published in 2014 revealed the absence of lions, but at least 46 hyenas were recorded in the park's savanna ecosystem.

[9][27] Species include the African fish eagle, black-backed cisticola, black-throated apalis, black-winged pratincole, eastern wattled cuckooshrike, forest robin, forest wood hoopoe, great snipe, green pigeon, grey parrot, grey-headed broadbill, lesser kestrel, Pel's fishing owl,[9] pied kingfisher,[7] red-capped crombec, red-throated cliff swallow, Uganda woodland warbler, and yellow-capped weaver.