The systematic comparison of two border regions in southern Africa and North America in the second half of the 19th century makes a contribution to imperial history with analyzes of the functional mechanisms of imperial state formation and intercultural coexistence. With this decentralized, peripheral approach, the special character of actors and structures through the specific political space, the imperial border region, becomes clear. Political and cultural aspects of the illegal arms trade and its actors are in the foreground. Both represented both a stabilizing and a destabilizing element in the state penetration of the imperial border region, depending on the interests and actions of the actors involved, which were influenced by the local political and economic situation.