Still Growing Together? The Spatial Distribution and Industrial Composition of U.S. County GDP since 1870

We construct the first estimates of U.S. county GDP by broadly defined industrial sectors from 1870 to 2018. U.S. GDP per worker inequality has two broad eras: from 1870 to 1970 U.S. counties grew together, as states converged and inequality within states fell. Manufac- turing became less concentrated and more equally productive, explaining much of inequality’s decline. But U.S. counties stopped growing together after 1970. GDP inequality within states increased as the most productive metro areas increasingly decoupled from the rest of the state. GDP per person inequality increased even more than GDP per worker, driven by increasing employment-to-population inequality. Replacing manufacturing as the path to riches, tradable services, such as finance and business services, became increasingly concentrated in rich ar- eas, while poor areas’ economies became dominated by government, education, and health services. Troublingly for growth, the most productive counties’ populations no longer grow more rapidly than in other counties.