View metadata for key information about this dataset.Zip Code Tabulation Areas were developed by the US Census Bureau to overcome difficulties in precisely defining the land area covered by each Zip Code. The ZCTAs are generalized area representation of the USPS Zip code service areas, but are not the same as Zip codes. There is no correlation between ZIP codes and Census Bureau geography. In addition, the USPS frequently realigns, merges or splits ZIP codes to meet changing needs. ZCTAs are constructed by aggregating the Census 2000 blocks whose addresses use a given ZIP code. The census bureau took the ZIP code used by the majority of addresses in each census unit at the time the data was compiled. As a result, some addresses end up with a ZCTA code that is different from their ZIP code.This Zip code polygon layer has an accompanying arc layer.For questions about this dataset, contact max.steinbrenner@phila.gov. For technical assistance, email maps@phila.gov.