The present invention is a method that enables a business with multiple locations within a LATA to use a single number for its service. All callers dial the same number to reach the subscriber's business, and a network routes the calls to the most appropriate subscriber location based on the geographic location of the caller, time of day, day of week, and/or percent distribution among subscriber locations. The geographic location of the caller is determined using the calling party number (NPA-NXX-XXXX) and either mapping this number to a wire center (using the NPA-NXX) or to a block group (using the entire NPA-NXX-XXXX). An advantage of Area Number Calling is the granularity of block group routing. Block groups are defined by the Census Bureau and typically encompass a much smaller geographic area than a wire center. Block groups are defined by the Census Bureau for the entire United States. Block groups tend to encompass four to twelve blocks, and they honor natural boundaries, like rivers. This gives an ANC subscriber a greater degree of flexibility in defining which geographic areas should be routed to which subscriber locations. The present invention also provides a method of reducing the amount of geographic data that is transmitted to or stored on a database associated with the routing equipment by routing as a unit intersecting regions of multiple subscriber data tables.