This article appraises kin availability and migration timing on French-Canadian child mortality in an early twentieth-century North American industrial city. The analysis is based on the exploitation of an original dataset constructed by linking the 1910 census data (IPUMS-Full Count) for Manchester, New Hampshire to Quebec Catholic marriage records (BALSAC) and geocoding census data at the household level (Sanborn Fire Insurance Maps). Our results suggest that the presence of maternal and paternal grandmothers in the city living in different households were associated with reduced child mortality and that French-Canadian women who arrived in the United States as children or young adults experienced higher child mortality compared to second-generation French Canadians and those who migrated at a later age.