The Central African Republic occupies an immense rolling plateau that forms, along a crest that trends southwest to northeast, the major drainage divide between the Lake Chad and Congo River basins. The country is well supplied with waterways. Tributaries of the Chari River occupy the northern third of the country’s territory. The remaining two-thirds of the terrain drains southward into the Ubangi River, which forms the Central African Republic’s southern border with Congo (Kinshasa).