Boston in the second half of the 19th century is described by Sam Bass Warner Jr.

According to Warner, “No period in Boston’s history was more dynamic than the prosperous years of the second half of the nineteenth century. In fifty years it changed from a merchant city of 200,000 inhabitants to an industrial metropolis of over a million. In 1850 Boston was a tightly packed seaport; by 1900 it sprawled over a ten-mile radius and contained thirty-one cities and towns.”