Explaining Undocumented Migration to the U.S.

Using data from the Mexican Migration Project and the Latin American Migration Project, we find that undocumented migration from Mexico reflects U.S. labor demand and access to migrant networks and is little affected by border enforcement, which instead sharply reduces the odds of return movement. Undocumented migration from Central America follows primarily from political violence associated with the U.S. intervention of the 1980s, and return migration has always been unlikely. Mass undocumented migration from Mexico appears to have ended because of demographic changes there, but undocumented migration from Central America can be expected to grow slowly through processes of family reunification.