It was not just a movement of human souls that shook the order of Hampshire County, but a movement of human bodies as well. During the middle of the eighteenth century New England became a society marked by a sharp increase in geographical mobility, and a large number of the migrants pushed into western Massachusetts. In discussing migration in colonial New England, most historians have tended to emphasize its significance for the older towns the migrants left: out-migration represented, for instance, a necessary response to the growing land scarcity that resulted from population pressure and overcrowding or, put perhaps more accurately, from the unequal distribution of land and wealth. Useful though these analyses are, they tell only half the story. We know less about the effect of migration on the region receiving large numbers of new migrants. In the case of Hampshire County it proved to be quite dramatic. Between 1740 and 1775 the flood of migrants sweeping into the county created a rapid surge of growth and expansion, a sharp increase in both the population and the number of towns. People soon came to live up in the hills as well as down in the valley, in new towns as well as in old ones, in poor towns as well as in prosperous ones.