This article examines how and why US interior immigration enforcement rates shifted over the past half century. Combining administrative, census, and archival data, results show a more extensive history of interior enforcement than previously documented. Findings further identify the state’s expansion of immigrant “illegality” and enhanced apprehension capacity as the key mechanisms driving the post-1990s increase in the interior deportation rate. Although these developments affected noncitizens from all regions, Latin American noncitizens were disproportionately impacted. Connecting these findings with scholarship on the controlling effects of deportation and the threat of deportation, this article argues that above and beyond a “deportation boom” or era of “mass deportation,” recent interior enforcement trends reflect a control boom. This concept captures the various tools the state employs to regulate the lives of noncitizens, especially Latinx noncitizens, and centers the extent of state control, rather than high deportation levels and rates, as the key phenomenon distinguishing the post-1990s interior enforcement era.