My dissertation consists of three essays. In the first, I systematically document the importance of chance to a fundamental question of economic geography: How did locations develop their specializations in specific manufacturing industries? I show that European immigration to the United States affected the initial location of industries in the late nineteenth century, creating a spatial pattern that remained relatively stable. Immigrants' exposure to specialized manufacturing knowledge and skills depends on their origin. The comparative advantage that came to U.S. counties ``embodied'' in immigrants predicts employment in disaggregated manufacturing industries in subsequent decades. The early establishment of firms in novel industries ga...