Abstract
The Midwest made the transition from primary to secondary activity before 1880 by developing a large diversified industrial sector to serve burgeoning midwestern demand for manufactures. Because the Midwest had industrialized, its firms were able to compete with eastern producers in multiregional and national markets after 1880, when the transportation and communication systems were fully integrated. Supporting evidence is drawn from a national set of 327 urban-industrial counties, with a focus on the Midwest.