Tracking Urbanization and Exurbs: Migration Across the Rural-Urban Continuum, 1990-2016.

This paper summarizes annual migration patterns across the rural-urban continuum in the USA between 1990 and 2016. We introduce a modified rural-urban continuum classification, the Rural-Urban Gradient (RUG). The RUG holds metropolitan classification constant, effectively designates exurbs, and distinguishes central city core counties in major metropolitan areas from their suburbs and exurbs. The RUG is used to compare, over time and across regions, net migration, and migration efficiency using annual county-level data from the Internal Revenue Service. Results show how migration patterns correlated with changes in demographics and housing depending on counties' location along the RUG. We also describe the extent to which rural migration flows converged in counties at metropolitan peripheries and concentrated in the South and West, thus shaping widening disparity across US rural contexts.