The Okomu National Park, formerly the Okomu Wildlife Sanctuary, is a forest block within the 1,082 km² Okomu Forest Reserve in the Ovia South-West Local Government Area of Edo State in Nigeria. The park is about 60 km north west of Benin City. The park holds a small fragment of the rich forest that once covered the region, and is the last habitat for many endangered species. It continues to shrink as villages encroach on it, and is now less than one third of its original size. Powerful corporations are involved in plantation development and logging concessions around the park, which also pose a threat.
The 200 km² wildlife sanctuary, a rainforest ecosystem that is the habitat for many endangered species of flora and fauna, was gazetted from the Okomu Forest Reserve in 1935. A survey of southwestern forests in Nigeria in 1982 led to a recommendation for a determined effort to conserve the sanctuary. The state government formally defined the sanctuary in 1986, with an area of just 66 km2. The Nigerian Conservation Foundation (NCF) took over management of the sanctuary in 1987, and extended it to 114 km2 by adding a one-mile wide buffer zone.
The park is drained by the Osse River which defines its eastern boundary. The Okomu River forms the western boundary. Rainfall is between 1,524 and 2,540 mm per year. Soils are acidic, nutrient-poor sandy loam. Vegetation is Guinea–Congo lowland rain forest, including areas of swamp-forest, high forest, secondary forest, and open scrub. Among the common trees are Kapok, Celtis zenkeri, Triplochiton scleroxylon, Antiaris africana, Pycnanthus angolensis and Alstonia congoensis. The park is probably the best example of mature secondary forest in southwest Nigeria.
The park has diverse fauna, with 33 species of mammals including the African buffalo and the endangered African Forest Elephant. Elephant sightings are rare, although in 2007 a one-year-old elephant carcass was found, unlikely to have died from natural causes. Park officials claim that elephant poaching no longer occurs, despite the high prices commanded for ivory in Lagos. About 150 species of birds have been identified. These include Angolan Pitta, Grey Parrot, Wrinkled Hornbill, Fish Eagle, hawks, woodpeckers, Great Owl, Grey Hornbill, Cattle Egret, Black-casqued Hornbill, Yellow-casqued Hornbill, Sabine's Spinetail, Cassin's Spinetail, Black Spinetail, White-breasted Negrofinch, Chestnut-breasted Negrofinch, Pale-fronted Negrofinch and Yellow-throated Cuckoo.