What does it mean to be of Irish descent? What does Irish descent stand for in Ireland? In Northern Ireland? In the United States? How are the categories of “native” and “settler” and accounts of ethnic origin being refigured through popular genealogy and population genetics? Of Irish Descent addresses these questions by exploring the contemporary significance of ideas about ancestral roots, origins, and connections. Moving from the intimacy of family stories and reunions to disputed state policies on noble titles and new applications of genetic research, Nash traces the place of ancestry in interconnected geographies of identity—familial, ethnic, national, and diasporic. Underlying these different practices and narratives are potent and profoundly political questions about who counts as Irish and to whom Ireland belongs. Examining tensions between ideas of plurality and commonality, difference and connection that run through the culture and science of ancestral origins, Of Irish Descent is an original and timely exploration of new configurations of nation and diaspora as communities of shared descent.