Migration-related detention, the administrative incarceration of people lacking legal authorisation to remain, has become a standardised technique used by states to violently regulate and discipline undesired mobility. As carceral junctions, migration detention camps serve to identify, confine, symbolically punish and expel people deemed ‘out of place’ in the national order of things. As bordering mechanisms, they are techniques of sorting and controlling populations, and sites where we can observe the enforcement of state racism. These processes of racialisation and expulsion operate corporally and affectively. Drawing on ethnographic fieldwork with prison officers working inside Denmark's migration-related detention camp, and engaging with the literature on race, emotion and border criminology, the article traces the role of racial affect in forging the identities of people interacting inside the camp. It demonstrates how prison officers’ racialised suspicion, compromised compassion, and passionate nationalism partake in making incarcerated migrants into expellable subjects, and in ordering them in accordance with matrices of racial differentiation. The officers’ emotions, I argue, should be understood as part of the camp's infrastructure, and productive for the border regime.