Chad is a land-locked country in north-central Africa with a total area measuring 1,284,000 km2. Chad's neighbours include Libya to the north, Niger and Nigeria to the west, Sudan to the east, Central African Republic to the south, and Cameroon to the southwest. The country's topography is generally flat with broad arid plains in the centre, desert in the north and lowlands in the south. The elevation gradually rises from Lake Chad northwards towards the Tibesti Mountains along the border with Libya and east to the Ennedi Plateau and the Ouaddaï highlands. Emi Koussi, a shield volcano lying at the south end of the Tibesti Mountains, rises to 3415 m and is the highest mountain in Chad, and the highest in the Sahara. Lake Chad, bordered by Chad, Niger, Nigeria, and Cameroon, is the most significant water body in the Sahel and is one of the most important wetlands on the continent. The lake has shrunk dramatically in the last four decades and currently covers only 1350 km2 down from 24,800 km2. It is fed by the Chari and Logone Rivers, both of which originate in the Central African Republic.

Chad has four bioclimatic zones: the arid Saharan region which covers roughly the northern third of the country, the central semiarid Sahelian region or Sahel and a southern region divided between the tropical to subtropical Sudanian zone and humid tropical Guinea zone. 


The geology of Chad is characterised by Precambrian metamorphics and sediments surrounding the central Chad Basin. Precambrian rocks occur in the Tibesti Mountains in the north and the east. There is a large area of basement rocks exposed in eastern Chad which extends across the border into the Darfur region of Sudan. The dominant lithologies are granitic gneiss and pelitic-graphitic schists both cut by numerous late orogenic granites and pegmatites. Lower Paleozoic sandstone sequences in the Kufra Basin in the northeast are overlain by Nubian Sandstones. The Lower Cretaceous is made up of continental clastic rocks whilst rocks of the Upper Cretaceous are marine.

Tertiary sediments cover part of southern Chad and the Neogene Chad Formation comprises lacustrine sediments within the Chad Basin.  Chad's mineral resources include bauxite, gold, quartz, uranium, tin, and tungsten.