My dissertation considers the relationship between slave-emancipation and prison reform in the Anglophone-Atlantic world. In particular, I examine the rise of a trans-Atlantic reform community in England and British North America that began to simultaneously advocate for the penitentiary model of punishment and the abolition of slavery. I trace how these reform sensibilities evolved into state policies of emancipation and prison reform in the northeastern United States and the British Caribbean at the turn of the nineteenth century, paying attention to the role of new systems of incarceration in structuring post-emancipation society and the ways in which former slaves increasingly came to be subject to new punishment regimes that constrained the possibilities of legal freedom. I argue that the penitentiary served to enforce order in the context of slave-emancipation and the birth of liberal freedom, influencing subsequent emancipation projects in the French Caribbean, U.S. South, and Brazil and leaving a lasting legacy of black incarceration visible in contemporary mass incarceration.