Geocast communication mechanism allows to deliver messages to a group of hosts in a certain geographical area. The geographic target area is identified by either geometric address or symbolic address. Some routing protocols are already implemented for this specialized form of multicast inWireless Ad-hoc Networks. Until now, each of them supports only one of these two addresses. It is the same with symbolic geocast routing using symbolic addresses. In previous work, symbolic geocast routing allows geocast communications only between two participants in one symbolic location model might representing a building. Generally, a medium-scale network covers several buildings and blank areas in between them. Geometric addresses must be used in blank areas as the reason that construction of symbolic location model is difficult for the entire network. To develop a geocast routing protocol supporting hybrid geographic addressing (symbolic and geometric), we first present a novel hybrid location model for integrating geometric location model with several symbolic location models at the same time. Second, hybrid geocast routing algorithm takes use of existing symbolic geocast routing and Greedy Perimeter Stateless Routing (GPSR) to build a new routing system. Third, a transition mechanism called “bridge” is proposed to bridge the gap between two different symbolic location models. It is required that a bridge includes the transition of addressing schemes and the transition of routing algorithms. Hybrid geocast routing algorithm forwards geocast messages with symbolic addresses indoors using symbolic routing and geocast messages with geometric addresses outdoors using GPSR. The simulator Ns-2 is used to evaluate the performance of hybrid geocast routing. In extensive evaluations, the routing algorithm achieves high message delivery rates but with only 50% longer than the theoretic optimal paths.