An improved decoding and processing system is provided for advanced determination and display of geographic information to a called party relating to the call origination party. The improved system comprises a receiving device to receive an MDMF or SDMF format message from a local CO switch containing call identification data; a microcontroller storage and retrieval device containing a data base library for selectively determining the corresponding geographic information such as city and/or state by matching the area code and/or local exchange number received from the call origination party; and a readout device for displaying the city and/or state of the incoming call. Preferably, the system includes capability to automatically update the data base library of the storage and retrieval device as new area codes and/or local exchanges are subsequently assigned. Accordingly, the improved system provides the user with convenient and efficient display of geographic information related to caller identification that is capable of determining an ever increasing number of area code and local telephone exchange numbers.