How can humanitarian actors operate in a host state with significant subnational variations in willingness and capacity to meet its obligations? This is an issue of pressing importance, given the expansion of humanitarian aid to middle-income countries with growing state capacity, but with persistent infrastructural weakness in their periphery. The article illustrates the challenges and potentialities of engaging these states through the case study of the Norwegian Refugee Council (NRC) in Colombia. It describes the way the NRC has located its offices in peripheral areas, and how its activities have fostered the rule of law, successfully using rights-based approaches to strengthen subnational state institutions, activate and mobilise citizen demands and bridge national and subnational administrations. The article concludes that these activities, operated by officers with extensive practical knowledge and local trust networks, can open the way for durable solutions for humanitarian crisis, but can also provoke backlash from subnational actors.