This paper examines the distribution of languages in the Nigerian Middle Belt, draws certain historical inferences from the patterns of distribution, and assesses non-linguistic evidence tending to confirm or refute these inferences. The Middle Belt is taken as an area roughly inscribed by the Hausa-speaking area to the north, and the Yoruba, Edo, and Ibo-speaking areas to the south. Geographically it is an area which has a certain climatic coherence, falling between the sahel to the north and the forest to the south (Pullan, 1962; Buchanan, 1953). It is also an area of much more strikingly broken terrain than those to the north or south, with not only the complex relief of the Jos Plateau, but also many ranges of hills, particularly along its northern frontier and in its eastern half. This terrain appears to have militated against the establishment of large coherent political systems in the past and it is only in the plains of the Niger and Benue valleys that there is a record of extensive state systems in recent history, those of the Nupe and Jukun. On the other hand, archaeological evidence indicates that the Nok culture extended over a very large area of the Middle Belt, not by any means confined to the plains (Fagg, 1959, 1969), and there is evidence of a certain measure of cultural unity today (Murdock, 1959).