USA Telephone Area Code Boundaries

U.S. Telephone Area Code Boundaries provides the telephone area code boundaries of the United States for use in telecommunications analysis. U.S. Telephone Area Code Boundaries represents the telephone area code boundaries for 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 area code is divided geographically, with one portion retaining the current area code and the other switching to the new area code. When a new NPA is added as an overlay, the current area code remains unaffected. Instead, all or part of the land covered by the current area code is now covered by the current and new area codes. The source of this dataset is TomTom (June 2023) and the layer is updated annually.美国电话区号边界数据集（U.S. Telephone Area Code Boundaries）提供美国境内的电话区号边界信息，用于电信领域的分析工作。本数据集收录美国全境的电话区号边界信息，此类电话区号覆盖的地理区域也被称为编号计划区域（Numbering Plan Areas，缩写为NPA）。编号计划区域的边界信息会同步反映最新且准确的边界调整情况，涵盖两种场景：一是全新的编号计划区域从既有编号计划区域中拆分而来，二是全新的编号计划区域叠加覆盖至既有编号计划区域之上。当编号计划区域被拆分时，该区号覆盖的地理区域将被按地域分割，其中一部分保留原有区号，另一部分则切换为新的区号。若以叠加方式新增编号计划区域，则原有区号不会受到任何影响，原区号覆盖的全部或部分地理区域，将同时由原有区号与新区号共同覆盖。本数据集的数据源为TomTom（2023年6月），且其图层信息每年都会进行更新。