This polygon shapefile contains the boundaries of telephone area codes in the United States. They are also known as Numbering Plan Areas (NPA). The Numbering Plan Areas reflect current and accurate boundary changes both where new NPAs split from existing NPAs and where new NPAs overlay existing NPAs. When an NPA is split, the geographic area covered by the old area code is divided geographically, with one portion retaining the previous area code and the other switching to the new area code. When a new NPA is added as an overlay, the old area code remains unaffected. Instead, all or part of the land covered by the old area code is now covered by two area codes. Data are represented at a scale of 1:250,000. This layer is part of the 2014 ESRI Data and Maps collection for ArcGIS 10.2. U.S. Telephone Area Code Boundaries provides the telephone area codes of the United States for use in telecommunications analysis. ESRI and TomTom North America, Inc. (2014). United States Telephone Area Code Boundaries, 2014. ESRI. Available at: http://purl.stanford.edu/wq040jg5974