The UDS Mapper displays ZCTAs, not ZIP Codes. ZCTAs are the U.S. Census Bureau’s approximation of ZIP Codes, and while in most instances the ZCTA code equals the ZIP Code for an area, not all ZIP Codes have their own ZCTA. The UDS Mapper contains updated national ZCTAs reflecting U.S. Postal Service ZIP Code changes through October 2010, and there may not be any further updates of ZCTA boundaries until the 2020 Census. Therefore, since U.S. Postal Service ZIP Codes can change at any time as needed for efficient delivery of the mail, ZIP Codes exist that have not been converted to ZCTAs. To address this issue, in their annual preparation of Uniform Data System data from Health Center Program (HCP) awardees and look-alikes, HRSA assures that every valid ZIP Code maps to the ZCTA that best fits its location. Therefore, reported health center patients are never left out of counts/analyses due to new or changed ZIP Codes. Note: within the reference geography (e.g., reflected in the search and zoom functions) underlying this tool, ZIP Codes are included. Therefore, you can enter a ZIP Code that is not a ZCTA and zoom to that area, but may not see the ZIP Code number or area represented on the map. This is because there is no ZCTA for that ZIP Code. Although you will be seeing the correct area, it will not be labeled as such.