The 19th century is recognised as a period of mass emigration from Cornwall, with a significant proportion of the male population leaving to work overseas, mainly in the mining industry. Less appreciated is that many of these migrants were married men who left wives and children behind in Cornwall. This study seeks to shed some light on the experiences of these women, known as 'married widows'. It adopts a multi-faceted approach, which draws upon crowd-sourcing and digital resources, in combination with more traditional methodologies. Scattered and fragmentary qualitative evidence (drawn from correspondence, newspapers, remittance and poor law records, supplemented by personal testimony recorded in family histories) is examined within a quantitative framework produced by an innovative database created from census records and a longitudinal study of outcomes. This thesis describes how tens of thousands of wives were 'left behind' in the mining communities of Cornwall, and the wide range of resources they drew upon in the absence of their husbands. It examines the interaction between the wives and the State in the form of the Poor Law and the Courts, identifying a pragmatic response to the needs of the emerging transnational nuclear family. Male migration from Cornwall is revealed to vary widely in type, intent and duration, leading to great diversity of experiences and outcomes for the wives 'left behind'. The establishment of temporary male labour emigration from the Cornish mining communities is shown to have occurred earlier than in many other emigration centres, creating greater potential for cultural acclimatisation to the challenges of spousal separation. The findings of this study challenge existing, generalised, perceptions of the wives as passive victims in the Cornish emigration story. Levels of destitution or desertion appear low compared to the scale of the phenomenon, and wives are shown as active participants and influential voices in family strategies. Nonetheless, this study highlights the vulnerability and greater risks faced by the wives 'left behind', and identifies financial and emotional insecurity as common elements of their experience. This thesis demonstrates a methodology and reveals insights that might be applied to the study of wives 'left behind' in other parts of the British Isles, and a comparator for existing studies of those elsewhere in the world.