This polygon shapefile contains zip code boundaries for the United States. Data are valid from July to September, 2007. Attributes included in the data are location, area/perimeter, county names, FIPS and USPS codes, and alternate names. These data are updated quarterly using the latest feeds from the U.S. Postal Service with additional sources being used to cross-check the data. This layer provides zip code data for view and analysis in GIS and interactive web mapping applications.