The Topography of Masai Mara National Reserve consists mostly of gently rolling to flat plains at 1000 meters elevation, surrounded by hills and escarpment, which range up to 2290 meter elevation. Within Reserve micro climatic variation is noticeable due to the elevation. The metamorphosed sediments of the Basement System are underlying large areas of central and southern parts of Narok district. Nguruman escarpments, west of the Mara River have exposed rocks of quartzites, gneisses, schists, amphibolites, migmatites, mylonites and pegmatites. Loita, Siana hills and hills around Lemek are dominated by quartzites derived from original sandstones and grits.
In the Masai Mara National Reserve the drainage is determined by topographic conditions. The Mara ecosystem is drained in a south - easterly direction because it is sloping gently downward to the Southwest from Lemek Hills. Mara River originates from Mau Hills flowing south west through footslope of the Siana escarpment then south through Mara National Reserve turning west and discharging into Lake Victoria. All the watercourses in the plains drain into Mara River. The Sand River and Talek, the largest tributary of Mara River, drain the National Reserve and Siana Plains. Most of the tributaries dry up during the dry season except Mara and Talek rivers.
The vegetation of Mara ecosystem varies from grasslands to shrublands to wooded grasslands and shrubby and wooded riverine. 'Pure' grassland communities are widely dominated by Themeda triandra, Bothriochloa insculpta, and Setaria phleoides, whereas the open grassland plains are dominated mostly by Themeda triandra.
The central plains where most of the wild herbivores graze comprise short and tall as well as wooded grassland. The wooded grasslands that are mainly composed of Balanites to Themeda triandra are found mainly in the Mara triangle, which is located in western part of the park. Shrubby grassland community is dominant within the Mara Reserve, Loita Hills and southern parts of Koyaki ranch.
Generally, the physiographic condition of Masai Mara which the author has noticed and found in literature is as mentioned above. This area is not totally hilly, but the reserve's 50% area is hill and upland. The rest is slope and flat and the author suggests that this area can be ranked as upland.
