Immigration scholars have traditionally focused on the role of national borders and the significance of nation-state citizenship. At the same time, local government scholars have called attention to the significance of local boundaries, the consequences of municipal residency, and the influence of the two on the fragmentation of American society. This paper explores the interplay between these two mechanisms of spatial and community controls. Emphasizing their doctrinal and historic commonalities, this article suggests that the legal structure responsible for local fragmentation can be understood as second-order immigration regulation. It is a mechanism that allows for finer regulatory control than the crude boundary and membership regulations at the national level. It also serves as a means by which, in the absence of a national consensus, the competing interests surrounding immigration can still be negotiated and reconciled on the ground. Not only does this framework provide a conceptual bridge that unifies boundary and membership controls that until now have been perceived as disparate and unconnected areas of law, but it also raises important questions about policies at the heart of today’s immigration debates.