Serengeti National Park is a 14,763 km² (5,700 sq mi) protected savanna in northern Tanzania, covering the eastern Mara Region and northeastern Simiyu Region between the Ngorongoro highlands and Lake Victoria. Established in 1940 and on UNESCO’s World Heritage List since 1981, it is the core of a wider Serengeti ecosystem of about 30,000 km² that runs north into Kenya’s Maasai Mara and lies between 920 and 1,850 m above sea level. Its landscape grades from treeless short-grass plains in the southeast, through the Western Corridor of the Grumeti and Mbalageti rivers, to the hilly woodlands of the north, and it carries the Great Migration of about 1.5 million western white-bearded wildebeest and 250,000 zebras on a loop of roughly 800 km.
The park makes most sense crossed on the ground. What follows is a journey from its southeastern edge, where most visitors arrive from the Ngorongoro highlands, through the centre at Seronera, west along the rivers to Lake Victoria and north to the Mara River on the Kenyan border, naming what changes on the way.
From the Ngorongoro Highlands Onto the Volcanic Short-Grass Plains
Arriving from the southeast means coming off the Crater Highlands, and their shadow explains the park’s first landscape. Sheltered by those highlands, the southeastern Serengeti receives as little as 508 mm of rain a year, the lowest in the ecosystem. Until 1959 this ground was all one park; that year 8,300 km² in the east was split off as the Ngorongoro Conservation Area, to accommodate the traditional land use of the Maasai, and that conservation area now borders the park to the southeast.
The plains are almost treeless, and the reason is underfoot. The soil here formed on ash from the Crater Highlands volcanoes: Kerimasi, a 2,602 m shield volcano that erupted about 150,000 years ago, and Ol Doinyo Lengai, the only active volcano on Earth known to erupt natrocarbonatite lava. The rapid weathering of that natrocarbonatite ash left layers of calcareous tuff and a calcitic hardpan soil, and on it grassland, not woodland, dominates. Ecologists call these the Serengeti volcanic grasslands, an edaphic community, meaning one set by soil rather than climate. After the rains this short grass is where the herds gather to give birth.
East of the park boundary, inside the Ngorongoro Conservation Area, the Oldupai River cuts Olduvai Gorge, about 48 km long and up to 90 m deep, into the sediments of a Pleistocene lake bed. Its name comes from the Maasai word for the wild sisal that grows along it, and the excavations of Mary and Louis Leakey made it one of the key sites for early human evolution.
Kopjes, Lake Ndutu and the February Calving Grounds
Rising out of the grass are kopjes (also spelled koppies), islands of rounded granite boulders. They are the tops of Archaean granite-gneiss plutons between about 2.72 and 2.56 billion years old, uplifted around 180 million years ago. In a landscape with almost no trees, they serve predators as observation posts. Leopard density in the park has been estimated at 5.41 per 100 km² in the dry season.
On the southern edge of the plains lie two small soda lakes, Lake Ndutu (also called Lake Lagarja) and Lake Masek. Ndutu is seasonal; in the dry season it recedes to broad mudflats and can dry out completely, while in especially wet years an ephemeral stream links it to Masek, and the two lakes feed the ephemeral Oldupai River. In 1973 excavations at the lake uncovered the Ndutu cranium, a partial skull of an early hominin. The surrounding acacia, Commiphora and Balanites woodland and the open grass around the lakes are the calving grounds. The herds arrive in December, and in February the wildebeest give birth to around 500,000 calves in a burst of two to three weeks. When the lake is high, animals that try to swim across can drown in their thousands.
The two rainy seasons decide the timing. The long rains fall from March to May and the short rains in October and November. As the long rains end in May the plains dry out fast, and the herds turn northwest.
Seronera: Airstrip, Lodges and the 1966 Research Institute
Heading northwest across the plains brings you to Seronera, the main settlement in the park. Nobody is allowed to live inside the boundary except park staff, researchers and the people who work at lodges and camps, and most of them are based at Seronera, which has the park’s main airstrip. It is also the scientific heart of the Serengeti. The Serengeti Research Institute was founded here in 1966 to monitor the Great Migration, seven years after Bernhard and Michael Grzimek’s 1959 book and film Serengeti Shall Not Die made the park internationally known.
The centre is lion country. More than 3,000 lions live in the wider ecosystem, the largest lion population in Africa, though an outbreak of canine distemper in 1994 killed about a third of them. The area also shows how the edges and the core of the park differ: Masai giraffes fell from about 10,750 in 1977 to 3,520 in 2010, and since then the population has stabilised in the centre of the protected area while still declining towards its edges.
Down the Western Corridor Along the Grumeti and Mbalageti to Lake Victoria
From Seronera a long tongue of the park runs west almost to Lake Victoria. This is the Western Corridor, defined by a pair of rivers, the Grumeti and the Mbalageti, which like the Orangi and the Mara drain west into the lake. The Grumeti lies almost entirely within the corridor and enters Lake Victoria’s Speke Gulf. The land is flatter than the north and more thickly vegetated than the southern plains, with small ranges of hills, and the rivers are lined with gallery forest where yellow and olive baboons, vervet monkeys and black-and-white colobus (mantled guereza) live.
The migration passes through the corridor from about May to July, and between May and August thousands of wildebeest cross the Grumeti. Around 3,000 crocodiles wait at the Grumeti and Mara crossings. Rainfall rises to about 1,200 mm a year on the lakeshore, more than double the plains in the southeast, and near Lake Victoria floodplains have formed on ancient lakebeds. Beyond the park boundary the Grumeti and Ikorongo game reserves buffer the corridor to the west and Maswa Game Reserve covers the southwest, but outside them the pressure is human: a 1996 study found the population on the western side growing by about 4 percent a year, with farming and ranching spreading towards the park.
North Through Commiphora Woodland to the Mara River and the Kenyan Border
The northern Serengeti, from Seronera up to the border, is remote and relatively inaccessible. Its landscape is dominated by hills and open woodland, mainly Commiphora, and in the far northwest the woodland changes again, to broad-leaved Terminalia and Combretum on different rock. That northwestern corner gets the highest rainfall in the system and is where the herds find grass at the end of the dry season.
The river that makes it possible is the Mara, the only permanently flowing river in the whole Serengeti ecosystem. It rises at about 2,932 m in the Napuiyapi swamp on the Mau Escarpment in Kenya, flows through the Maasai Mara National Reserve, enters the Serengeti at the border and continues west to Lake Victoria, about 395 km in all. About 65 percent of its 13,504 km² basin lies in Kenya. Beginning in July, the herds pile down its banks to cross, and they arrive in Kenya in late July and August, staying through the dry season.
In early November the short rains return, and the herds begin moving south again, reaching the southeastern plains in December, in time for calving in February. Around 250,000 wildebeest and 30,000 zebras die each year on the circuit from drowning, predators, exhaustion, thirst or disease. Poaching drove the big animals down in the 1980s: the eastern black rhinoceros fell to about 10 individuals and still numbers fewer than 70, while African bush elephants had recovered to more than 5,000 by 2014.
The 452 km Highway Plan and the Edges Under Pressure
The journey ends where the Serengeti’s problems begin: at its edges. To the northeast and east lies the Loliondo Game Control Area, and beyond the Kenyan border deforestation in the Mau Forest has altered the flow of the Mara, the river the whole migration depends on in the dry season. Between 2005 and 2012 the government considered a 452 km highway through the park, a plan revived in 2024; supporters argue it would connect and develop northern Tanzania, while conservationists warn it could cut the migration route, and southern routes around the park have been proposed instead.
Other pressures are quieter. A 2001 estimate by the World Conservation Monitoring Centre put poaching at roughly 200,000 animals a year, and invasive plants such as Siam weed, prickly pear and Mexican sunflower are spreading. Tanzania and Kenya give legal protection to more than 80 percent of the Serengeti, yet the ecosystem is now about 60 percent of its original size.
For the month-by-month movement of the herds, read our guide to the Great Migration in the Serengeti; for the caldera on the park’s southeastern doorstep, see Ngorongoro Crater; and for the rains that set the whole calendar in motion, our overview of the climate of Tanzania explains the long and short rainy seasons across the country.