Trends in national and regional population concentration in the United States from 1790 to 1990: from the frontier to the urban transformation

The United States has undergone sizable changes in its population geography since 1790. A major component of these population shifts has been the rapid movement of the frontier westward as settled area increased. This research shows the population deconcentration effects of the great migration from relatively high densities along the eastern seaboard to the sparsely populated west. This dispersal was followed by concentration stemming from massive urbanization across most of the country after the general “closure” of the frontier during the first decade of the 20th century. This paper examines these levels of population deconcentration or dispersion and concentration in the nation and among regions from 1790 to 1990. Additionally, this research supports the argument for a 1910 date of frontier “closure” through evidence from national population concentration trends. A three-phase model of population concentration and dispersion at the regional and national levels is also proposed. The Hoover index is employed to measure population concentration using county-level population data and digital county maps aggregated at the regional and national levels from all decades from 1790 to 1990.