Dwindling U.S. Internal Migration: Evidence of Spatial Equilibrium?

This paper examines whether the significant downward shift in U.S. gross migration rates after 2000 is indicative of the economy nearing a stationary spatial equilibrium. Nearness to spatial equilibrium would imply that site-specific factors such as amenities and location within the urban hierarchy have little influence on migration because their values have been capitalized into prices, causing interregional utility levels to become approximately equal. Yet, in an examination of U.S. counties, we find empirical evidence of only a mild ebbing of natural amenity-based migration after 2000 and little slowing of population redistribution from peripheral towards core urban areas. Instead, the primary finding is a downward shift in the responsiveness of population to spatially asymmetric demand shocks post-2000, and associated increased responsiveness of local area labor supply, more consistent with European regional labor markets. Quantile regression analysis suggests that this shift does not relate to a difference in regional labor market tightness across the two decades.