This new entity was developed to overcome the difficulties in precisely defining the land area covered by each ZIP code.
[2] Moreover, the USPS frequently realigns, merges, or splits ZIP codes to meet changing needs.
Each ZCTA is constructed by aggregating the Census 2020 blocks whose addresses use a given ZIP code.
ZCTAs are not developed for ZIP codes that comprise only a small number of addresses.
[3] Several ZCTAs represent ZIPs that no longer exist due to realignment by the USPS.