census.gov-zcta_county-2.1.2 Last Update: 2022-04-25T18:11:30
Maps Cenus zip-code tabulation areas to Counties
This file links Ztca regions -- the Census version of ZIP codes, to counties, by associating a Zcta with the county that contains the Zctas centroid.
There are only about 1/2 the number of Zctas in this file ( 33K ) as there are ZIP codes ( about 77K )
Note that the ZCTA regions are joined to counties after converting the geometries to EPSG 4326 (WGS84), from the original 4269 (NAD 83). The discrepancy between these CRS is only a few meters, so this should not make a difference.