The eighty years from 1790 to 1870 were marked by dramatic economic and demographic changes in the United States. Cities in this period grew faster than the country as a whole, drawing migrants from the countryside and immigrants from overseas. This dynamism stemmed from cities’ roles as spearheads of commercial change and sites of new forms of production. Internal improvements such as canals and railroads expanded urban hinterlands in the early republic, while urban institutions such as banks facilitated market exchange. Both of these worked to the advantage of urban manufacturers. By paying low wages to workers performing repetitive tasks, manufacturers enlarged the market for their products but also engendered opposition from a workforce internally divided along lines of sex and race, and at times slavery and freedom. The Civil War affirmed the legitimacy of wage labor and enhanced the power of corporations, setting the stage for the postwar growth of large-scale, mechanized industry.