How does the new institutional ecology of city politics structure opportunities for urban growth? We draw on policy agendas theory to explore two central aspects of this question: the process by which urban actors attempt to reach development policy goals by “shopping” for alternative institutional venues and the conditions under which extraurban institutions—such as state and special-purpose governments—provide favorable alternative decision settings. We conduct a comparative case study of two prominent megaprojects—Chicago’s new Comiskey Park (1986-1991) and Seattle’s Safeco Field (1994-1995)—in which policy-making authority shifted from city government to extraurban venues. Our analyses illustrate how the interplay of several factors, including the resources and capacity of relevant coalitions and the issue politics that surround the project, shape venue-shopping opportunities for urban megaprojects. In advancing these arguments, this research underscores the more general significance of venue shopping in urban growth policy processes.