Abstract: Within the past decade, U.S. interior immigration enforcement has shifted away from the street and into the jailhouse. The rationale behind jailhouse screening is to target enforcement efforts on those who fall within federal removal priorities. This Article shows how a program undertaken with the stated aim of targeting immigration enforcement has had precisely the opposite effect: it has massively expanded the reach of immigration enforcement and created extended carceral treatment within the criminal justice system based on suspected immigration status. This approach, in turn, leads to removals that lack adequate process, are inaccurate, or that reflect underlying racial biases in criminal arrests. Jailhouse immigration screening resuscitates what is experienced as a punitive model of immigration enforcement but without the procedural protections that ought to accompany the criminal process. This approach imposes an enormous cost on racial minorities disproportionately subject to low-level arrest, and it cuts against immigration enforcement officials’ stated aim of targeting immigration enforcement. By laying bare how jailhouse screening extends the impact of criminal arrest, undermines due process, and magnifies racial disparities, this Article makes the case for uncoupling immigration screening from the jailhouse altogether. Barring that approach, arrested immigration screening from the jailhouse altogether. Barring that approach, arrested individuals are entitled to greater front-end procedural protections, including neutral review of immigration detainers.