Do ZCTAs reflect commercial ZIP Codes?
The ZCTA delineation process included both residential and commercial addresses. A ZIP Code representing a commercial district may appear as a ZCTA if the ZIP Code serves the majority of the addresses for the census blocks in the area. However, individual firms or organizations with their own ZIP Codes are automatically excluded and do not become ZCTAs. There are 2,523 of these unique ZIP Codes excluded from Census 2000 ZCTA delineation.