As over 30 million people moved to North America during the Age of Mass Migration (1850-1913), governments feared that Europe was being depleted of its most talented workers. I use new longitudinal data from the early twentieth century to study the geography and selectivity of migration from Ireland, the European country with the highest emigration rate. I find that Irish-speakers and the sons of farmers in poorer communities, where emigrant networks were strongest, were more likely to move to the United States. These results indicate that highly skilled workers were, in fact, underrepresented in the flow to America.