Census data by zip code: free download. On-line document store on 5y1.org

[DOCX File]ZIP Code Data - Internal Revenue Service
https://info.5y1.org/census-data-by-zip-code_1_4e28d8.html
Nearly 97 percent of the returns match on the 9-digit ZIP code. When the 9-digit ZIP code is not available, the matching process uses the 5-digit ZIP code to determine the proper congressional district. Returns that do not match on ZIP code, or where a ZIP code is not present, are excluded from the data.
census figures by zip code

[DOCX File]ZIP Code Data
https://info.5y1.org/census-data-by-zip-code_1_df1372.html
County data are based on population data that was filed and processed by the IRS during the 2019 calendar year. State totals within the County data may not be comparable to State totals published elsewhere by SOI because of disclosure protection procedures or the exclusion of returns that did not match based on the ZIP code.
census zip code level population

[DOC File]UNITED STATES OF AMERICA
https://info.5y1.org/census-data-by-zip-code_1_2f0817.html
OCA/USPS-T14-13. You have presented Census data by ZIP Code for the square miles of territory covered. The ZIP Codes you have used are encoded. Independent research on the data and subsequent matching of data are accordingly impossible. Please provide the following data by encoded ZIP Code for the same year as your square-mile data:
demographic information by zip code

[DOC File]Data Resource List
https://info.5y1.org/census-data-by-zip-code_1_f68df9.html
data is easily available at the ZIP code and “census designated place” levels and American Community Survey data is offered for various ethnic, race and ancestry groups as well as at various geographic levels from the largest cities (Miami, Hialeah, Miami Beach, and …
us census zip codes

Census data by zip code