The lagoon region (zone lagunaire) is a narrow coastal belt extending along the Gulf of Guinea from the Ghana border to the mouth of the Sassandra River. It consists of a strip of low, sandy islands and sandbars built by the combined action of heavy surf and ocean currents. These sand barrierÍÍÍÍs, known as the cordon littoral, have almost closed the rivers flowing into the gulf. The resulting series of lagoons ranges in width from about a hundred meters to seven or eight kilometers and seldom rises more than thirty meters above sea level, leaving the area subject to frequent flooding during rainy seasons.

Most of the lagoons are narrow, salty, and shallow and run parallel to the coastline, linked to one another and the gulf by small watercourses or canals. Where large rivers empty into the gulf, broad estuaries extend as much as ten to twenty kilometers inland. The sandy soil supports the growth of coconut palms and salt-resistant coastal shrubs. The dense rain forest that once came down to the water's edge along the continental side of the lagoons has been largely supplanted by clearings for farms and towns and by second-growth woodlands. In the few remaining undisturbed areas, dense mangrove thickets appear along the edges of marshy inlets.

Data as of November 1988