The land consists of an undulating plateau varying in altitude from 610 to 762 m (2,000–2,500 ft). Two important escarpments are evident: in the northwest is a high granite plateau (rising to 1,420 m/4,659 ft), which is related to the Adamawa Plateau of Cameroon; in the northeast the Bongos Range rises to 1,368 m (4,488 ft) and extends into Sudan.
Soils are complex: sands and clays predominate, sometimes covered with a lateritic layer, over granite and quartz rocks. The land is well drained by two river systems: the Ubangi and its tributaries in the south, and the tributaries of the Chari and Logone rivers in the north.