A "carceral state" represents a critical definitional contrast to the more commonly invoked frames of "mass incarceration" or "mass criminalization." Mass criminalization scholarship is typically focused on the most proximate causes and consequences of growth in the size of the criminal legal system. In contrast, conceptualizing mass incarceration as merely the most visible feature of a broader carceral state expands the analytical landscape but results in significant tradeoffs. In this article, we engage narratives of the development of carceral states, noting that they resist simple or widely agreed-upon definitions, and vary with respect to how they engage crime, race and racism, politics and the political economy, and the importation of carceral logics to seemingly unrelated institutions. We conclude by reflecting on what can be gained by understanding the United States as a carceral state, rather than simply a nation with persistently high crime and punishment rates.