Based on fieldwork undertaken in 2004–2005, I analyze how the Irish border has been constructed, represented, challenged, and imagined by both the state and borderlanders as a means to discuss processes of constructing sovereignty. I focus on the concept of “assemblage” to integrate and highlight the tensions and contradictions between different levels of analysis: the juridical, the academic representation of the border, and the memories and practices of borderlanders. I argue that sovereignty, rather than a claim to be taken at face value by states, is the emergent property of the combination of a variety of forces, forms, and practices involved in the making of borders, and that its very enactment also produces anti-sovereign effects.