ABSTRACT
The Middle Ganges Valley, which lies midway between the dry Upper Ganges Plain and the very wet Delta region, has always constituted an admirable environment for human settlement. the annual precipitation is more than in the Upper Ganges Valley, but less than in the region of the Deltas and, as naturally expected in regions in which the entire agricultural economy depends on the monsoon, the density of population varies directly as the amount of annual precipitation. It is the physical characteristics which determine the possibilities of extension of cultivation and the consequent growth of population. The northern portion includes the fertile, alluvial plain of Tirhut where the natural conditions are highly favourable to expansion of cultivation. It is only in the sub-montane districts of Champaran on the west and Purnea on the east that the density of population has been low, and there is still room for expansion of cultivation.
