Large-scale infrastructures are often understood by state planners as fulfilling a national integrative function. This paper challenges the idea of infrastructures as national integrators by engaging theories of state/nation formation and infrastructure in a postcolonial context. Specifically, I put Lefebvre's characterization of the production of state space as a homogenization-differentiation dialectic in conversation with Gramsci's understanding of hegemony, bureaucracy, and nationalism to analyze the controversy surrounding the giant Tarbela Dam in Pakistan in the 1960s. I use the Tarbela controversy as a case study to elaborate a theory of postcolonial nation-formation through state-led infrastructural projects. I argue that in a postcolonial context the failure to articulate a hegemonic nationalist ideology to accompany the production of large-scale infrastructure results in a fragmentation of state space in some ways, even as state space is homogenized and integrated in other ways. The paper also offers a "hydraulic lens" on the politics of regionalism in Pakistan. © 2015 Antipode Foundation Ltd.