Sahelian Chad lies between the Sahara Desert to the north and the more fertile savanna territory to the south. It is populated primarily by nomadic people.
The semiarid Sahelian zone of Chad, forms a belt about 500 kilometres wide that runs from Lac and Chari-Baguirmi prefectures eastward through Guéra, Ouaddaï, and northern Salamat prefectures to the Sudanese frontier. The climate in this transition zone between the desert and southern Soudanian Chad is divided into a rainy season (from June to early September) and a dry period (from October to May).
In the north of the region, thorny shrubs and acacia trees grow wild, while date palms, cereals, and garden crops are raised in scattered oases. Outside these settlements, nomads tend their flocks during the rainy season, moving southward as forage and surface water disappear with the onset of the dry part of the year. The centre is characterized by drought-resistant grasses and small woods. During the hot season, in April and May, maximum temperatures frequently rise above 40 °C. In the southern part, rainfall is sufficient to permit crop production on unirrigated land, and millet and sorghum are grown. Agriculture is also common in the marshlands east of Lake Chad and near swamps or wells. Many farmers in the region combine subsistence agriculture with the raising of cattle, sheep, goats, and poultry.
Lake Chad is the remains of one of the largest lakes in the world - slowly being depleted by the area's growing need for water. There are substantial surrounding wetlands.