This article explores the historical production of immigrant illegality in the United States as a set of interrelated yet distinct racial projects. The passage of nineteenth and twentieth century immigration legislation, which instituted requirements for immigrant identification, transformed unskilled labor movements from China and Europe into unauthorized or improperly documented immigration. This illegality was differently racialized. Excluded as a group, Chinese entrants became wholesale associated with illegality. In contrast, though it far surpassed the numbers of unauthorized entrants from China, European illegal movement was quickly forgotten. Unauthorized immigration from China and Europe were met with tightened immigration law and enforcement. Set in motion by the regulation of Chinese and European immigration, this “spiral of illegality” created the context for the transformation of Mexican laborers into indocumentados in the twentieth century and continues to shape the conditions under which twenty-first century immigrants arrive and live in the United States. While Mexican nationals have been the largest group to have arrived undocumented in the United States, today they constitute about half of the undocumented population, which hails from everywhere in the world, including nations in Asia and Europe. Recognition of such intersections among undocumented immigrant groups questions widespread assumptions about the existence of sharp distinctions between contemporary and historical immigration, and it also contributes to emerging forms of cross-ethnic activism for immigrant rights that complicate notions of indocumentados as nationals of one particular country.