The territory now known as Chad possesses some of the richest archaeological sites in Africa. During the seventh millennium B.C., the northern half of Chad was part of a broad expanse of land, stretching from the Indus River in the east to the Atlantic Ocean in the west, in which ecological conditions favored early human settlement. Rock art of the "Round Head" style, found in the Ennedi region, has been dated to before the seventh millennium B.C. and, because of the tools with which the rocks were carved and the scenes they depict, may represent the oldest evidence in the Sahara of Neolithic industries. Many of the pottery-making and Neolithic activities in Ennedi date back further than any of those of the Nile Valley to the east.

In the prehistoric period, Chad was much wetter than it is today, as evidenced by large game animals depicted in rock paintings in the Tibesti and Borkou regions. Recent linguistic research suggests that all of Africa's languages south of the Sahara Desert (except Khoisan) originated in prehistoric times in a narrow band between Lake Chad and the Nile Valley (see Languages and Ethnic Groups , ch. 2). The origins of Chad's peoples, however, remain unclear. Several of the proven archaeological sites have been only partially studied, and other sites of great potential have yet to be mapped.

Data as of December 1988