We develop an urban growth model where human capital spillovers foster entrepreneurship and learning in heterogenous cities. Incumbent residents limit city expansion through planning regulations so that commuting and housing costs do not outweigh productivity gains. The model builds on strong...

The received economic wisdom is that cities are too big and that public policy should limit their sizes. This wisdom assumes, unrealistically, that city sites are homogeneous, migration is unfettered, land is given freely to incoming migrants, and federal taxes are neutral. Should those...

A key reason for the existence of cities are the externalities created when people cluster together in close proximity. During Covid, such interactions came with health risks and people found other ways to interact. We document how cities changed during Covid and consider how the persistence of...