This chapter examines several dimensions of the regional political economic framework linking US foreign policy interests to migration and refugee flows. It reviews the history of migration flows from south of the border into the United States. The numerical dimensions of the regional flow constitute a complex story, especially if debates on the magnitude of illegal migration are included. The chapter examines the technical discussions over whether the volume of Mexican illegal immigration is 500,000, 12 million, or somewhere in between. It explains the various administrative and legislative actions used to organize and regulate this regional immigration. The chapter summarizes several variations in the conceptualization of the value of migration in regional development strategies. It describes an abbreviated account of the relationships between domestic and foreign policy concerns and the reform of US immigration laws in the 1960s. The social composition of the post-1965 migration has been strongly influenced by the policy compromises in the 1965 amendments.