An attraction inside the conservation area, not the same thing as it
The crater and the conservation area are routinely treated as one place, and they are not. The Ngorongoro Conservation Area is a multiple land use area of some 8,000 square kilometres containing highland forest, several other calderas, the Olduvai and Laetoli archaeology, the Gol Mountains and a resident pastoralist population. The crater is one feature inside it. Gate hours, vehicle rules, the prohibition on off-road driving and the prohibition on walking on the crater floor are all set by the authority for the area as a whole, and the parent guide sets them out. This page is about the caldera.
What the Ngorongoro Conservation Area Authority publishes about it
The NCAA describes the crater as the world’s largest intact and unfilled volcanic caldera and the conservation area’s main visitor attraction, and lists it among Africa’s Seven Natural Wonders. It gives the formation as roughly 2.5 million years ago, when a volcano the authority likens in scale to present-day Kilimanjaro erupted and collapsed inward. Its published dimensions are an area of almost 260 square kilometres, a diameter of approximately 20 kilometres and a collapse depth of 610 metres.
One point in that description is worth pulling out, because it corrects the commonest mental picture of the place. The NCAA states that the crater is a natural formation allowing animals to wander in and out freely throughout the year. It is not an enclosure and the animals in it are not trapped. What concentrates them is water and grazing rather than the walls.
The habitats the authority names on the floor are grassland, swamp, river and woodland. That mixture inside a single caldera is the reason a day here looks nothing like a day on the plains.
Where the authority contradicts itself, and which figure is used here
A block of frequently asked questions repeated at the foot of several NCAA pages gives the crater a diameter of 16 kilometres and a crater wall of over 600 metres, along with counts of hyena, wildebeest and zebra. That block is not the NCAA’s own writing. It tells readers that Ngorongoro is managed by a different authority and directs them to another website for fees, which the NCAA plainly would not say about itself, and its figures do not match the authority’s own crater page. The numbers above are the ones from the crater page, and the animal counts in the pasted block are not repeated here.
This matters beyond pedantry, because the 16 kilometre figure has been copied onward into a great deal of travel writing.
What the crater is, and what it is not
It is the most concentrated resident large-mammal viewing in Tanzania and the realistic answer for black rhino in the country, which the big five safari guide explains. No rhino count appears here; the published figures disagree with each other, none carries a census year, and the locations are security-sensitive.
It is not a migration destination. The herds calve on the short-grass plains around Ndutu in the south-west of the conservation area and cross into the Serengeti; they do not come down into the caldera. Anyone whose trip is built around the migration is booking the wrong part of the area for it.
And it is not walkable. Walking safaris are prohibited on the crater floor, though they are permitted on the rim and elsewhere in the area, and every walk anywhere in the conservation area must be accompanied by an armed ranger. The craters that are walked rather than driven are Empakaai and Olmoti.
Common questions
How big is the Ngorongoro Crater?
The NCAA’s crater page gives almost 260 square kilometres, a diameter of approximately 20 kilometres and a collapse depth of 610 metres. A widely copied alternative figure of 16 kilometres across comes from a third-party text block repeated on other NCAA pages and does not match the authority’s own description.
Is the crater the same as the conservation area?
No. The conservation area is the whole protected block and the crater is one feature within it. Most published rules, hours and fees apply to the area rather than to the caldera specifically.
Are the animals trapped in the crater?
No. The NCAA is explicit that animals move in and out freely throughout the year. The concentration is a response to permanent water and grazing, not to the walls.