Understanding long-run patterns in the incarceration of Black Americans requires integrating the study of racial inequality with the study of political economy. I offer a parsimonious framework describing how the Black incarceration rate has been affected by the dynamics of exploitation and exclusion over time and across space. This framework helps to explain otherwise puzzling facts, like why the Black incarceration rate was lower in the South than in the North for much of the 20th century, why it was lowest in the South’s cotton belt, and why it began to tick upward when it did. It also enables us to better understand recent changes in racial and class inequality in incarceration in the United States.