In this paper we propose a new routing protocol and address scheme, Geographically Informed Inter-Domain Routing (GIRO). GIRO departs from previous geographic addressing proposals in that it uses geographic information to assist, not to replace, the provider-based IP address allocation and policy-based routing. We show that, by incorporating geographic information into the IP address structure, GIRO can significantly improve the scalability and performance of the global Internet routing system. Within the routing policy constraints, geographic information enables the selection of shortest available routing paths. We evaluate GIRO's performance through simulations using a Rocketfuel-measured Internet topology. Our results show that, compared to the current practice, GIRO can reduce the geographic distance for 70% of the existing BGP paths, and the reduction is more than 40% for about 20% of the paths. Furthermore, encoding geographic information into IP addresses also enables GIRO to apply geographical route aggregation, and a combination of geographic and topological aggregation can lead to 75% reduction of the current BGP routing table size.