The Kanyok live in Central Africa where the rim of the Zaire River basin joins the northern edge of the vast southern savanna plateau. The plateau and the central basin were separated more than 100 million years ago when the southeast half of Africa experienced a series of geological uplifts while northwestern Africa was flooded by advancing seas. Today, the transition between the elevated south and the lower north is clearly evident in Kanyok territory where rivers and roads starting in the south drop, at times abruptly, as they wind their way north.

Two distinct deposits of sediment and glacial debris cover the region's ancient Pre-Cambrian base of metamorphic rock. One, the Karroo, dates back to about 250 million years ago when Africa was still part of Gondwanaland and when the south pole was in Africa. The other, the Kalahari, was created less than 100 million years ago after the breakup of the supercontinent. Both the Karroo and the Kalahari deposits formed thick horizontal layers of rock and sand. As the savanna rivers emerged and descended northward into the central basin, they carved a series of parallel valleys exposing and eroding the many layers of sediment compressed into sandstone, limestone, clayey shales, quartz, ferruginous rock, and sand. Once the valleys deepened, cross-cutting secondary streams flowed from the higher surfaces between the rivers and wore down the land separating the valleys. At the source of these smaller streams, which are still at work carving the savanna plateau, small erosional amphitheaters ate into the gently rolling hills.