This invention provides an apparatus and method for processing telephone numbers that assists telephone subscribers in reaching the desired destination when the area code is unknown or has changed. The invention can be integrated into a telephone unit, implemented as a stand-alone device connected to the subscriber's telephone line (including wireless, cable-TV lines, and other modes of telecommunication), implemented as a utility on a personal computer that may or may not be connected to the Internet or to a telephone line, or implemented as part of the telephone switching system. In a preferred embodiment, the apparatus for processing telephone numbers includes an area code processor and a caller interface. The area code processor has means, which are responsive to information about the called party, for producing a list of telephone numbers. The caller interface communicates with the area code processor and a calling party; and has means for monitoring call initiation signals, means for receiving called party information such as a telephone number, and means for selecting a target telephone number from the list of telephone numbers produced by the area code processor.