Chad, officially known as the Republic of Chad, is a landlocked country in north-central Africa. It is bordered by Libya to the north, Sudan to the east, the Central African Republic to the south, Cameroon to the south-west, Nigeria to the southwest, and Niger to the west. It has a population of 16 million, of which 1.6 million live in the capital and largest city N'Djamena.
Chad has several regions: a desert zone in the north, an arid Sahelian belt in the centre and a more fertile Sudanian Savanna zone in the south. Lake Chad, after which the country is named, is the second-largest wetland in Africa. Chad's official languages are Arabic and French. It is home to over 200 different ethnic and linguistic groups. Islam and Christianity are the main religions practiced in Chad.
Beginning in the 7th millennium BC, human populations moved into the Chadian basin in great numbers. By the end of the 1st millennium AD, a series of states and empires had risen and fallen in Chad's Sahelian strip, each focused on controlling the trans-Saharan trade routes that passed through the region. France conquered the territory by 1920 and incorporated it as part of French Equatorial Africa.