The recent level of illegal immigration to the United States has increased debates about the effect of these immigrants on the cost of public services, and states have begun to enact policies that limit the public services available to illegal immigrants. The central issues are how many illegal immigrants reside in particular local areas and states and their effect on public expenditures and revenues and the economy in general. The Local Fiscal Effects of Illegal Immigration workshop selected six studies for analysis. The six case studies focused on one specific aspect of the complex question of the demographic, economic, and social effects of immigration: the net public services costs of illegal immigrants to selected geographical regions.