This collection of articles addresses the interconnections between punishment, citizenship and identity. As immigration and crime control measures have intersected, prisons in a number of countries have ended up housing a growing population of foreign-national offenders and immigration detainees. It is somewhat surprising that criminologists have traditionally spent so little time exploring the relationship between the prison and national identity. With notable exceptions, scholars almost universally treat the prison as an institution bounded by and within the nationstate. This special issue seeks to disrupt that convention of prison studies and criminology more broadly. Focusing on the incarceration of foreign-nationals in diverse contexts, the contributions to this issue collectively argue that the prison is a projection of national sovereignty and an expression of state power. It is also a concrete space where global inequalities play out. When considered through the lens of citizenship, our understanding of imprisonment shifts to include other geographical sites both within the nation-state and elsewhere, the prison's intersections with other legal frameworks, and enduring matters of race, gender and class. The contributions capture these dimensions by weaving together policy analysis and first-hand narratives from around the world.