Published online by Cambridge University Press: 04 January 2016
Three Declining Plateaus of population growth provide an empirical framework for American social history (Nugent, 1981). After a pre-history, self-sustaining demographic regimes appeared in the form of a frontier-rural mode of life common to most Americans by about 1720 and remained unchallenged until the mid-nineteenth century. From the 1860s to the 1920s, the frontier-rural mode continued to exhibit considerable strength but in rapidly contracting areas of the Great Plains, Great Basin, and Columbia Plateau. During that period of fifty years, however, the second plateau was increasingly supplanted by the metropolitan (or urban-industrial) mode of life. After 1920, by demographic measures, the frontier-rural mode of life had been replaced virtually everywhere by the metropolitan one familiar to Americans ever since.