Even today, a traveller through the length and breadth of England is soon aware of cultural differences, some of which are clearly visible in the landscape. It is advocated by the eminent English historian Charles Phythian-Adams that England, through much of the last millennium, could be divided into regional societies, which broadly coincided with groups of pre-1974 counties. These shire assemblages in turn lay largely within the major river drainage systems of the country. In this unusual and probing study Alan Fox tests for, and establishes, the presence of an informal frontier between two of the proposed societies astride the Leicestershire-Lincolnshire border, which lies on the watershed between the Trent and Witham drainage basins. Many studies of rural landscapes tend to emphasise medieval and earlier times, but here the stress is on the early modern period. On either side of the proposed frontier, seven contrasting countrysides are distinguished; three in Leicestershire, three in Lincolnshire, with the seventh, former heath land, spanning the county boundary. Diversity in the underling geology and differential rates of enclosure resulted in marked contrasts in settlement distributions and population densities of the seven countrysides. Patterns of wealth, poor-relief, the local economy, land ownership and land use reveal further distinctions, but the crucial area was the heathland which separated two neighbouring societies. On either side of this frontier, echoes of traditional cultural differences, particularly of customs, folklore, dialect and vernacular architecture, can still be experienced today. The evidence presented suggests a strong case for a cultural frontier zone, which is announced by a largely empty landscape astride the border between the contrasting settlement patterns of these neighbouring counties. The author finally adds further proof for the existence of this divide backwards and forward in time from the early modern period. It is hoped that this original approach will encourage researchers to identify other regions and their frontiers by adopting similar methods.