Congo is located in the central-western part of sub-Saharan Africa, along the Equator. To the south and east of it is the Democratic Republic of Congo. It is also bounded by Gabon to the west, Cameroon and the Central African Republic to the north, and Cabinda (Angola) to the southwest. It has a short Atlantic coast.

The capital, Brazzaville, is located on the Congo River, in the south of the country, immediately across from Kinshasa, the capital of the Democratic Republic of the Congo.

The southwest of the country is a coastal plain for which the primary drainage is the Kouilou-Niari River; the interior of the country consists of a central plateau between two basins to the south and north.