This paper explores the social interactions of immigration, occupation and wealth in two urban industrial cities of nineteenth century New England that were largely built upon, and shaped by, immigration: the very rapidly growing factory town of Holyoke, Massachusetts and a more mixed market and steadily growing nearby community of Northampton, Massachusetts. Both communities were emergent, rapidly industrializing, inland cities, providing a quite distinct immigration context than large established cities of the East Coast. Both were destinations for the same general ethnic immigration waves over the late nineteenth century, but with very different, and differently impacted, social spaces into which immigrants arrived. Contrasting and considering both these emergent cities allows us to ascertain the extent to which the occupational distribution and accumulation of wealth by immigrant groups supports the broad pattern of nineteenth-century assimilation, and reveals ways in which other migration processes may have been at odds, or intertwined, with the long-term historical assimilation of immigrants in such communities. Our findings support a traditional assimilationist perspective in emergent urban-industrial centers. However, they also reveal the role of universal immiseration in an industrial city dual-labor market in facilitating or forcing assimilation, the temporal advantages for ethnic groups of arriving early in growing settlements, and the more individualistic nature of economic enclaves in gaining advantages over time that did not manifest across broad immigrant or occupational groups.