This article explores how the humanitarian presence and programs in the disputed border area of Abyei between Sudan and South Sudan can be understood as a buffer between conflicting parties, rather than as mere assistance to a displaced population. It aims to contribute to debates about the spatial impact of humanitarian governance and the politicization of aid in protracted crisis contexts, and specifically in relation to territorial disputes and border struggles. It is based on ethnographic fieldwork in South Sudan between 2011 and 2013. The article argues that the humanitarian response became part of the politics of belonging that lies at the heart of the dispute. The very acts of labelling, categorizing, and maintaining the subjects of aid are highly political, such as the creation of the category of the 'people of Abyei' in contrast to refugees or Internally Displaced People. As a result, the interventions have sustained governance over the territory and can be understood as a humanitarian buffer that may shape the border area of Abyei for many years to come.