Borders are perhaps the most significant institutions in international relations. A massive literature demonstrates that border disputes fundamentally affect the character of relations between disputants, often escalating to violent and persistent conflict. However, the literature has barely begun to explore and identify the exact mechanisms that produce disputes and whereby these disputes escalate. Recent research demonstrates that how borders are drawn affects the probability of subsequent conflict and suggests that borders will be peaceful when they effectively and efficiently coordinate the actors on either side, thereby creating stable and predictable patterns of interactions. This research, however, ignores the obvious temporal component implied by theory. We develop the temporal component of an institutional theory of borders, starting from the argument that whether new international borders become more stable over time depends upon whether actors on both sides learn to coordinate on new jurisdictional international borders. We build on this idea to argue that the effect of time is significantly influenced by the manner in which the new border is drawn. We find that new borders that follow previous administrative frontiers become stable institutions much faster than than those drawn otherwise. In other words, stable and peaceful coordination on new borders occurs much faster when those new borders follow previous administrative frontiers.