USGS National Boundary Dataset (NBD) Downloadable Data Collection

The USGS Governmental Unit Boundaries dataset from The National Map (TNM) represents major civil areas for the Nation, including States or Territories, counties (or...美国地质调查局（USGS）国家地图（The National Map, TNM）行政单元边界数据集，涵盖美国全国范围内的主要行政区域，包括各州、领地及县（或……）