Description: While USPS does not make an up-to-date geographic layer of zip codes available, TEBS-GIS uses various available sources to provide as accurate boundaries as possible for zip codes used for mailing address. Because zip code areas overlap county boundaries, this layer - which cuts off at the county boundary - should not be used to join with statistics by zip code; zip codes that overlap with neighboring counties would not reflect the data accurately mapped to this layer. Census zip code tabulation areas do not cut off at county boundaries and thus are better suited for mapping statistics by zip code.