In this thesis, I present the design and evaluation of new techniques to solve the routing problem in large-scale city-wide wireless ad hoc networks. With an upsurge of wireless technologies, many routing protocols have been proposed for wireless ad hoc networks, but none of them have been proven capable of handling the tasks in a large-scale network that is composed of thousands of nodes. We propose a new routing scheme that is a hybrid of the current proactive and reactive routing mechanisms. This scheme uses proactive beaconing messages to build a virtual hierarchical coordinate system in an ad hoc network and thereafter uses reactive routing maintenance techniques to bypass the stale information between beacons. I implemented this new hybrid scheme in the network simulator ns-2. The simulation results show that it performs well in a large-scale ad hoc network of one thousand of nodes with low overhead.