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FIVE-DIGIT ZIP CODE BOUNDARIES FOR THE CONTERMINOUS UNITED STATES
Description:
The Five-Digit ZIP (Zoning Improvement Plan) Code boundary layer (zip5) is derived from the Geographic Data Technology (GDT), Inc. ZIP Boundary and Inventory Files (v. 5.0) and stored in the EPA Spatial Data Library System (ESDLS). This layer contains data for the conterminous U.S. and is divided into state directories that are contained in a ARC/INFO spatial data library in ESDLS. A ZIP code is a number of up to nine digits used by the U.S. Postal service to identify an area where mail is delivered. The zip5 boundary layer shows the boundaries for five-digit ZIP code delivery areas. The first digit of five-digit zip code divides the country into 10 large groups. Within these areas each state is divided into 10 smaller areas that are identified by the second and third digits. The fourth and fifth digits identify a post office, station, branch or local delivery area.