Under the Trump administration and its “zero-tolerance” policy, the number of detained asylum seekers in the United States has been growing significantly. Yet we know little about their mobility, agency, and social relations at the micro level during the time they are subject to a detention regime. This is because research about detention has frequently developed independently of sustained engagement with the lived experience of those detained within the relevant institutions. Building on literature about the spatiality of social relations and studies that analyze detention “from below,” the current article conceptualizes detention as a social space in which social relations between detained asylum seekers are formed and negotiated. It draws on ethnographic material collected in detention prisons in the greater New York City area and pays particular attention to the seemingly mundane social facets of everyday life in detention. The article reveals the complexity, ambivalences, and forms of social relations that range from shared and unifying feelings of injustice, to the development of friendships and shared practices of resistance and disobedience that sometimes even go beyond the confines of detention. This perspective allows us to see detained people as agents in the exercise of power and in negotiation with structures of control, waiting, punishment, and exploitation that organize but do not complete their everyday lives in detention.