The Masai Mara is Kenya's greatest wildlife reserve, a large extension of open plain grasslands, woodlands and smooth hills rich in some of Africa's most thrilling wildlife. Occupying an area of 320 km² in south-western Kenya, within the Great Serengeti ecosystem, it's effectively the northern continuation of the Serengeti National Park and game reserve in Tanzania.

The Masai Mara's quantity and variety of wildlife is breathtaking. The reserve is perhaps most famous for its lions, which are found in large numbers, and for the annual wildebeest migration, known as the Great Migration, largely considered one of World's most exceptional natural phenomena. Many other distinctive African wildlife are to be found in the Mara, from elephants, antelopes and giraffes to leopards and hyenas. Hippopotami and crocodiles are found in large groups all along the Mara and Talek Rivers. There is a reasonable population of the endangered black rhinoceros (in 2000 37 individuals were recorded) and of Cheetah, although their numbers are also threatened, chiefly due to tourist disruption of their day-time hunting.

Named for the Maasai people (the traditional inhabitants of the area) and the Mara River which divides it, the reserve is basically a mammal park, and although more than 450 bird species inhabit the area, birdwatchers could remain disappointed, as its much harder to spot one given bird species that, say, an elephant or, obviously, wildebeest.

And its precisely the large bearded antelope of the acacia savanna and short-grass plains, known also as gnu, the most numerous inhabitant of the Masai Mara (as it is of the Serengeti), with an estimated population of almost 2 million individuals living in the Great Serengeti ecosystem. Around July of each year, these ungainly social grazers migrate in a vast ensemble north from the Serengeti plains in search of fresh pasture, and return to the south around October. This circular, clockwise migratory route, the Great Wildebeest Migration, is one of the world's greatest natural events. Each year the promise of rain and fresh grass brings more than 1.3 million Wildebeest into a single massive herd, which makes a spectacular entrance on the southern plains of the Mara in a massive, surging column of wildlife.

Numerous other antelope can be found, including Thomson's and Grant's gazelle, impala, topi and Coke's hartebeest. Large herds of zebra are found through the reserve. The plains are also home to the distinctive Maasai giraffe as well as the common giraffe. The Maasai Mara is a major research centre for the spotted hyena. Additionally, over 450 species of birdlife have been identified in the park.

The Mara river, the reserve's backbone, traverses north to south heading for its westbound way unto lake Victoria, through the Tanzanian park. Its riverbanks (as well as those of the Mara's multiple tributary streams) are bordered by dense riverine forests where many the reserve's bird species are to be found. It's here, on the banks of the Mara River, where the migratory herds of the Great Migration make their mass crossing, that one of the most dramatic spectacles of nature is consumed. Live and death meet as the wildebeest, terrorized by the crocodile infested waters and churning currents yet obliged by their instinct, attempt to cross the river into the rich grasslands of the northern Masai Mara.

The entire area of the park is nestled within the enormous Great Rift Valley that extends from the Mediterranean Sea to South Africa. The terrain of the reserve is primarily open grassland, with clusters of the distinctive acacia tree in the south-east region. The western border is the Esoit Oloololo Escarpment of the Rift Valley, and wildlife tends to be most concentrated here, as the swampy ground means that access to water is always good and tourist disruption is minimal. The easternmost border is 224 km from Nairobi, and hence it is the eastern regions which are most visited by tourists.