The Ngorongoro Conservation Area (NCA) is a conservation area and a UNESCO World Heritage Site situated 180 km (110 mi) west of Arusha in the Crater Highlands area of Tanzania. The conservation area is administered by the Ngorongoro Conservation Area Authority, an arm of the Tanzanian government, and its boundaries follow the boundary of the Ngorongoro Division of Ngorongoro District. The Ngorongoro Crater, a large volcanic caldera, lies within the area.
A population of approximately 25,000 large animals, largely ungulates along with reputedly the highest density of mammalian predators in Africa, lives in the crater. Large animals in the crater include the black rhinoceros, the local population of which declined from about 108 in 1964-66 to between 11-14 in 1995, and the hippopotamus, which is very uncommon in the area. There also are many other ungulates: the wildebeest (7,000 estimated in 1994), the zebra (4,000), the eland, and Grant's and Thompson's gazelles (3,000).