Reforming and strengthening metropolitan governance are critical to attaining a growing, fair, and sustainable national economy. In today’s global economy, metropolitan areas are the relevant competitive unit. Firms make location decisions based on evaluations of entire metropolitan labor and housing markets and transportation systems, and not simply on evaluations of local areas. In addition, the scope of many important public policy concerns, such as congestion, pollution, and environmental issues, exceeds local boundaries to cover entire regions. Despite the growing relevance of metropolitan regions in the national and global economies, policy decisions are rarely made at the appropriate regional scale. In fact, most metropolitan areas in the United States are governed by highly fragmented systems that are dominated by local governments. High levels of political fragmentation produce inefficiency and inequality in metropolitan areas, undermining the possibility of fair and sustainable growth. Metropolitan areas could be reinvigorated by establishing regional institutions to coordinate decisions across policy areas in ways that promote efficiency and expand opportunity for all residents. The harms of regional political fragmentation are many and tightly interrelated. Political fragmentation provides incentives for inefficient land use practices and leads to sprawling residential development that consumes valuable natural resources in an unsustainable fashion. It stunts regional job growth by fostering zero-sum competition among local jurisdictions, providing minimal net developmental gains for the region as a whole. By boosting job sprawl and contributing to unclustered job growth, political fragmentation creates an unsustainable growth pattern that undermines the development of transit options. This contributes to ever-expanding congestion, accelerates the growth of regional vehicle miles traveled, and torpedoes the national efforts to curb greenhouse emissions. It encourages exclusionary zoning practices that geographically concentrate most of the region’s affordable housing stock in urban and inner suburban areas, which already struggle with high concentrations of poverty. By encouraging such harmful land use practices, fragmentation intensifies racial and economic segregation in metropolitan areas, undermining social and economic opportunities for low-income residents and residents of color who disproportionately live in the region’s opportunity-deprived, segregated neighborhoods. Finally, fragmentation deepens regional inequalities among local jurisdictions by intensifying their shortsighted and harmful competition for additional tax base.