Outamba-Kilimi National Park is located in northwest Sierra Leone near the border with the Republic of Guinea. The park is divided into two areas, Outamba (741 km²) and Kilimi (368 km²). The area became a game reserve in 1974, and was made a National Park in January 1986. The park is named after its highest peak in one part, Mount Outamba and its longest river in the second part, River Kilimi. The area was originally chosen for preservation as it contains a large number of chimpanzees. The vegetation is called woodland savanna, with a mixture of jungle and savanna.