My dissertation will examine the emergence of large-scale emigration between Mexico and the United States. I will use materials in private, public, and government archives in Mexico and the United States to demonstrate the centrality of migration to the governments and peoples of Mexico and the United States and the ways groups in both countries struggled to regulate the movement at different points between 1916 and 1946. As the first study to effectively situate emigration in the historiography of 20th century Mexico, my dissertation will serve as a timely intervention in Mexican scholarship. In the end, it will not only examine a movement long-neglected by historians of Mexico or illustrate the increasingly important role emigration played in post-Revolutionary debates, it will force scholars to rethink the role emigrants and emigration played in the defining events (including the land, labor, and religious conflicts) of 20th century Mexico. Perhaps most important of all, my dissertation will contribute to a better understanding of the historical and contemporary significance of Mexican migration to Mexico and the United States.