This article examines the domestic political sources of immigration control in advanced market economy countries after World War II. Immigration control can be distinguished from the broader concept of immigration policy by its emphasis on state policies that define the permissible level of resident alien admissions. The analysis is based on the well-established fact that immigrant communities are geographically concentrated. I argue that this geographic concentration creates an uneven distribution of costs and benefits, providing a spatial context for immigration politics. In this context, net public demand for tighter immigration control increases in localities where immigrants concentrate when those areas experience higher unemployment, rapid increases in immigration, higher immigrant proportions, and more generous immigrant access to social services. Each of these conditions aggravates competition between immigrants and natives, and hence native hostility, in these communities while employer support for immigration usually diminishes. Yet national politicians may ignore changes in the demand for immigration control unless these constituencies are also able to swing a national election from one party to another. The larger and less “safe” the local constituencies, the greater their influence in this sense. Evidence from the United Kingdom between 1955 and 1981 is consistent with these propositions.