The book considers illegality, deportability, and deportation in the lives of young people—those who migrate as well as those who are affected by the migration of others. A primary focus of the volume is to understand how children and youth encounter, move through, or are outside of a range of legal processes, including border enforcement, immigration detention, federal custody, courts, and state processes of categorization. Even if young people do not directly interact with state immigration systems—because they are U.S. citizens or have avoided detention—they are nonetheless deeply impacted by the reach of the government in its many forms. Combining different perspectives from advocates, service providers, attorneys, researchers, and, significantly, young immigrants, the book presents ethnographically rich accounts that can contribute to informed debates and policy reforms. By underscoring the ways in which young people encounter and/or avoid legal systems, the book problematizes the policies, laws, and legal categories that shape so much of daily life of young immigrants. The book makes visible the burdens, hopes, and potential of a population of young people and their families who have been largely hidden from public view and are currently under siege, following young people as they move into, through, and out of the complicated immigration systems and institutions in the United States.