This paper seeks to quantify the contribution of agglomeration economies to the spatial concentration of U.S. employment. A spatial macroeconomic model with heterogeneous localities and agglomeration economies is developed and calibrated to U.S. data on the spatial distribution of employment....

Recent concepts as megaregions and polycentric urban regions emphasize that external economies are not confined to a single urban core, but shared among a collection of close-by and linked cities. However, empirical analyses of agglomeration and agglomeration externalities so-far neglects the...