Decentralisation is a key reform in the fight against corruption, particularly in developing countries. However, both scholarship and policy often fails to account for the social-spatial relations that can determine the success of decentralisation reform. This article argues that this is a critical oversight that limits our understanding of the effectiveness of decentralisation reform to address corruption. It is grounded in fieldwork conducted with 136 public servants in four subnational administrations across Papua New Guinea. Reflecting on the impact of decentralisation reform, respondents described how elites were able to direct subnational resources â€“ sometimes for their own personal gain â€“ by reaching across space to control subnational affairs. Anti-corruption measures were largely ineffective because they were unable to reach out to anti-corruption organisations with adequate resources and political power. These findings suggest that topological approaches to understanding power relations â€“ approaches that stress the importance of reach across space â€“ could help scholars and policy makers reimagine the potential for decentralisation reform to address corruption.