Weak state capacity is one of the most important explanations of civil conflict. Yet, current conceptualizations of state capacity typically focus only on the state and ignore the relational nature of armed conflict. We argue that conflict arises where relational state capacity is low, that is, where the state has less control over its subjects than local, oftentimes ethnic elites. This occurs in ethnic groups that are poorly accessible from the state capital, but internally highly interconnected. To test this argument, we digitize detailed road maps of Africa, and convert them into a road atlas akin to Google Maps. We measure the accessibility and internal connectedness of groups via travel times obtained from this atlas. To address the endogeneity, we use an instrumental variable design based on road network simulations. We find that low relational state capacity is a key determinant of armed conflict in Africa.