--- - |2 Abstract Emerging attention to the spatial dynamics of political contention points to the spatially situated nature of mobilization, and, in turn, how space is socially produced through collective action. Drawing from interviews and archival research, this article examines an urban university social movement organization and its relationship to a larger social movement network in an urban context. In response to university administrators’ adoption of neoliberal policy reform, student activists challenged sociospatial boundaries in their organizing across scale—in their university, the city, region, and across the nation. By adopting a strategy of solidarity, student activists collapsed the boundaries of the university and transformed it into a hub of Leftist social movement organizing for the city and beyond, redefining scale. Findings suggest that the development of urban social movement networks can be understood as a scalar strategy of solidarity for building social movement persistence and power. This social movement network emerged in response to market and State redefinition of urban meaning at the transition to the 21st century. This article illustrates how the sociospatial formation of urban social movement networks challenges the boundaries of contention. - 'City &Community, EarlyView. '