Created in 1991 the Oban Division of Cross River National Park covers an area of around 3,000km² of lowland rainforest– the largest area of closed-canopy rainforest in Nigeria and contiguous with Korup National Park in Cameroon. Oban is an important watershed with hills rising above 500 m and one peak reaching approximately 1,000 m. The Oban Hills once formed part of one of the lowland rainforest refugia during the last glacial period and is an internationally recognized biodiversity hotspot and center of species richness and endemism particularly for primates, amphibians, butterflies, fish and small mammals.
Oban contains a number of rare species such as the Nigeria-Cameroon chimpanzee Pan troglodytes ellioti, the drill Mandrillus leucophaeus, leopard Panthera pardus, forest elephant Loxodonta cyclotis, the grey-necked rockfowl Picathartes oreas and the slender-snouted crocodile Mecistops cataphractus.
Oban is the only site in Nigeria where the Preuss’s red colobus monkey Procolobus preussi and the crowned guenon Cercopithecus pogonias can be found. The contiguous Oban-Korup forest is reputed to be the richest site in the whole of Africa for butterflies. Oban is also one of the richest and most ornithologically diverse sites in the country.
The Cross River National Park, together with the Oban Hills, forms the focus of the activities of the World Wildlife Foundation (wwf) in Nigeria. The park has a tropical climate characterized by a rainy season between April and October and a dry season between November and April.