A method and system is provided for tracking mobile devices combining packet processing technology with Global Positioning System (GPS) technology. A central network system comprising a packet processing subsystem receives transmitted GPS location data from a mobile device transmitting GPS location data, wherein the packet processing subsystem uses a table access scheme to process the GPS location data and produce responsive mapping data, and the central network processing system compares the mapping data to a map and identifies a corresponding map location. Embodiments may also correlate device identification data, tracking table entries, and/or billing zone charges. In some embodiments a look-up key is built responsive to the GPS location data and used to identify map locations. The table access scheme may be a key hashing scheme and, in particular, a longest prefix match type scheme.