This paper explores the analytic purchase and substantive concerns of what I am calling geographies of relatedness. Drawing on recent work in feminist anthropology which has reconsidered kinship as classificatory system and practice, and highlighting the attentiveness to sites, scales and contexts within this work, I suggest ways in which a focus on relatedness may shape approaches to established and emerging matters of concern in human geography. I consider first the foundational status but flexible meaning of ‘blood’ in kinship thinking, and the ways the flexibility of kinship can be curtailed and its foundational status reinstated in relation to the nation and the state. Second, I consider the geographies of relatedness that are constituted through and practised in the process of establishing degrees of biological connection, delimiting difference, mapping human ‘diversity’ and defining personal, collective and human origins at different scales and with different effects. A focus on geographies of relatedness, I argue, highlights the ways blood ties or similarly naturalized connections move between and connect categories of relatedness with different sizes, extents and configurations across space, as well as different temporalities. It suggests an alertness to new global mappings of human relatedness and difference and combines a critical attention to ideas of the ‘nature’ of human reproduction as foundational, original or primal in the natural order of the social, to ideas of ‘place of origin’: personal, national, ethnic, racialized, universal in their familiar and emergent forms.