The last thirty years witnessed a dramatic increase in the number of noncitizens detained in the United States. Individuals detained under immigration laws are held pending adjudication, often mandatorily, and without many basic constitutional protections. Immigrant detention imposes severe burdens on immigrants and their households and levies significant costs to society – financially, as well as in terms of social capital and community well-being. Chiefly due to the difficulty in accessing noncitizens in the process of detention and deportation, this system has largely escaped sociological inquiry. This presentation provides a background for understanding the growth and consequences of detention in the United States. It then presents findings from research based on administrative data, as well as surveys and in-depth interviews, about conditions of confinement and the impact of confinement on detained individuals as well as their families and communities.