People maximize their proximity to existing economic opportunities, showing little resistance to relocating as nation s economic fortunes change favoring different places over time. This effects growth of cities. The population is moving from rural to urban. Black migration from south to north, up to the 1940 s, is currently reversing. Migration is from north and east to south and west.
International immigration is from Mexico, Asia and Central America.
Affluent elderly retire in the sunbelt. Spatial distribution of the U.S. population is rooted in the colonial era of the 17th and 18th centuries dominated by England and France. The French were located in the continental interior while the English were located along the Atlantic seaboard. The interior was closed to settlement due to hostilities between France and Britain. Former Seaboard colonies had become separate culture hearths primary source areas and innovation centers.