The savanna vegetation of South Africa and Swaziland constitutes the southernmost extension of the most widespread biome in Africa. It extends beyond the tropics to meet the Nama-Karoo Biome on the central plateau, the Grassland Biome at higher altitudes towards the east and extends down the eastern seaboard interior and valleys where it grades into Albany Thicket in the Eastern Cape.
The geology of this area is dominated by a very stable block of ancient continental crust, known as the Kaapvaal Craton. The craton also hosts a number of significant sedimentary basins and igneous intrusions, thus preserving a geological record spanning most of geological time.
The major macroclimatic traits characterising the biome are seasonality of precipitation (alternation of wet summer and dry winter periods), and (sub)tropical thermal regime with no or usually low incidence of frost.