Abstract: Methods and systems to determine whether a directory number is classified as associated with other directory numbers or associated by local calling area. In a first method, a table of patterns is provided. Each pattern includes a terminating NPA-NXX designation that represents a directory number associated with a terminating device that may be dialed as a local call from an originating device having a local calling area pattern corresponding to the pattern to which this terminating NPA-NXX designation belongs. In response to receipt of an NPA-NXX portion, the pattern table is checked for a corresponding pattern and information is provided about the corresponding pattern. This information includes a terminating NPA-NXX designation. A determination may be made from the information as to what directory number may be dialed as a local call from the originating device having the NPA-NXX portion. In a second method, local calling area (LCA) pattern file including a plurality of LCA patterns is provided.