The expansion of the US carceral state has been accompanied by the emergence of what we call the ‘shadow carceral state’. Operating beyond the confines of criminal law and justice institutions, the shadow carceral state expands penal power through institutional annexation and legal hybridity, including: (1) increased civil and administrative pathways to incarceration; (2) the creation of civil ‘alternatives’ to invalidated criminal statutes; and (3) the incorporation of criminal law into administrative legal processes in ways that enhance state carceral power. Although legal doctrine deems civil and administration sanctions to be ‘not-punishment’, we call for a broad understanding of penal power and the carceral state.