The physical barriers defining the boundaries of the ecosystem are both ancient and relatively new. Although tribes have inhabited the region for centuries, their numbers and lifestyles have not affected the migration until the past few decades.
The Isuria Escarpment north of the Masai Mara Game Reserve forms the northern boundary. The growing agricultural human population on the Loita Plains and areas bordering the reserve limit the movements of the wildebeest in some areas of the north.
The forested Loita Hills in the northeast and Gol Mountains, continuing to the southeast, form the border on the east side of the ecosystem. At times however migrating wildebeest have grazed on the Salei Plains between the Gol Mountains and the Crater Highlands to the southeast. The dry woodlands along the Lake Eyasi Escarpment act as the boundary south of the plains.
Tribal agricultural settlements running along the Western Corridor and the Northern Extension of Serengeti National Park form a running barrier. Land use, human settlements and wildlife protection are less regulated and monitored. Consequently, poaching has been the most severe in these areas. The western-most tip of the ecosystem borders Lake Victoria.
