"Manufacturing industries differ with respect to their energy intensity, labor-to-capital ratio and their pollution intensity. Across the United States, there is significant variation in electricity prices and labor and environmental regulation. This paper uses a regression discontinuity approach to examine whether the basic logic of comparative advantage can explain the geographical clustering of U.S. manufacturing. Using a unified empirical framework, we document that energy-intensive industries concentrate in low electricity price counties, labor-intensive industries avoid pro-union counties, and pollution-intensive industries locate in counties featuring relatively lax Clean Air Act regulation. We use our estimates to predict the likely jobs impacts of regional carbon mitigation efforts"--National Bureau of Economic Research web site.