The Republic of the Congo covers an area of 342 000 km2 on either side of the equator, stretching from latitudes 3° 40´ N (on the north-west border with the Central African Republic) to about 5° S on the Atlantic coast (on the border with Cabinda). Three broad natural zones can be distinguished:
- The southern zone is bounded by Cabinda and the Democratic Republic of the Congo to the south, the Atlantic to the west, Gabon to the north and the central savannah zone to the east. It encompasses the administrative regions of Kouilou, Loukoumou, Niari and Bouenza. The first two are basically covered in forest (the Mayombe mountains in Kouilou and the Chaillu mountains in Loukoumou), while the other two are for the most part grass and shrub savannah;
- The northern zone, located for the most part north of the equator, is bounded by Gabon to the west, Cameroon and the Central African Republic to the north and the River Oubangui (the frontier with the Democratic Republic of the Congo) to the east. It corresponds roughly to the Cuvette, Likouala and Sangha administrative regions. It forms the Congolese part of the central basin, irrigated by right-bank tributaries of the Oubangui and the Congo, except for the Souanké area in the north-west, which is drained by tributaries of the Ogooué. Periodically flooded forests and thickets cover about a third of its area along the Oubangui for a width of 100 to 200 km, roughly between latitudes 2° 20´ N and 1° S. The remaining two-thirds are almost entirely covered by virtually intact closed forest;
- The central zone, consisting of the Plateau Batéké highlands and stretching roughly between latitudes 1° and 4° S (Brazzaville), lies between the two previous zones. It corresponds roughly to the Plateaux and Pool administrative regions and is almost wholly covered in grass or shrub savannah, apart from gallery forests and scattered islands of forest.
The climate is tropical, with high heat and humidity. The average annual temperature ranges between 23° and 27° while annual rainfall ranges from 1 200 mm in the Niari savannah area to 2 200 mm north of the Chaillu mountains, with three-quarters of the country having over 1 600 mm.
The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.