A promising communication paradigm that en- ables communication between IoT devices is broker-based publish/subscribe. When the brokers are distributed across the fog, events and subscriptions of clients connected to different broker instances must be routed across the router network. State-of-the art solutions, however, do not take into account that the relevance of the IoT data depends on its origin and purpose. Instead, they assume a uniform data distribution when determining where to match events and subscriptions which degrades system performance. In this paper, we propose a routing solution that builds upon geo-context information attached to published events and subscriptions. This way, we can match events close to either the publishers or subscribers of an event, thus, minimizing communication latency while not affecting scalability.