Recently, scholars have increasingly criticized descriptions of significant penal change as "ruptures"—sudden breaks with past practices, often replacing old technologies with new. This article promotes an alternative understanding of penal change as the layering of new penal technologies over old technologies to describe the complicated coexistence of old and new penal technologies following significant moments of change. This study demonstrates the layering process through a case study of the first major American penal reform: proto-prisons adopted between 1785 and 1822 are often described as the first great rupture in which long-term incarceration replaced capital punishment. Using the relationship between America’s emerging proto-prisons and declining death penalty, this article illustrates the complicated coexistence of penal reforms with older technologies. While proto-prisons emerged out of revulsion with capital punishment, many states adopted proto-prisons independently of their decisions to reduce capital offenses and most states retained relatively robust death penalties. Rather than a replacement or rupture, the emergence of proto-prisons represented an additional layer of punishment that partially displaced older technologies.