2020 Census Data by Zip Code

Apologies for the somewhat off-topic question.  Is there a source for PL94-171 redistricting data from the 2020 Census compiled by Zip Code Tabulation Areas?

  • I just tried to get ZCTAs from data.census.gov using the geos option and I get an error message.

    And NHGIS offers Zip Code Tabulation Areas, but I don't see data for 2020 Census redistricting data there, either... 

    Block-to-ZCTA crosswalk time?

  • Yes, the 2020 Redistricting Data files included no data for ZCTAs. I suppose this is because the Bureau hasn't (or hadn't) yet defined the official 2020 version of ZCTAs and are waiting to release 2020 summaries for ZCTAs until that is done. (As I recall, ZCTAs are updated with each new decennial census.)

    I don't know of any source of a 2020-block-to-2010-ZCTA crosswalk. The block data records in the 2020 Redistricting Files don't include ZCTA codes, so that's not an option. Right now, the best way to achieve this may be with a spatial overlay of 2020 TIGER/Line files for blocks and ZCTAs.

    BTW, another forum that's well suited for non-ACS census data questions (and I'm not saying it's wrong to pose a question like this here!) is the U.S. Census Bureau Slack channel: https://uscensusbureau.slack.com. 

  • NHGIS has released crosswalks from 2020 blocks to 2010 blocks, so another way to go about this is to allocate 2020 block data to 2010 blocks, and then use a 2010 block-to-ZCTA crosswalk to summarize by 2010 ZCTA. You can get associations between 2010 blocks and ZCTAs from GeoCorr or from an NHGIS 2010 block-level table data file.

  • Thanks Jonathan.  I'll probably use a spatial overlay in ArcGIS.  I was just looking for a shortcut.

    I was unaware of the Slack channel.  How does one get an account there? (We do not use Slack at my office.)

  • I think anyone can create a Slack account and join the Bureau's workspace. The link I shared before doesn't seem to make that very obvious, though! I just found another link on the Bureau's Developers page that takes you directly to this sign-up page.

  • Re: crosswalks -- 2020 ZCTA relationship files will be released at the end of November. (I recently emailed the Census geography program to ask whether a 2020 block to 2020 ZCTA assignment file was available, and that was their response).

  • Hi,

    I am very new to this forum, even not sure how to start a question.

    It is my first time to use zip code file to see children estimation, and realized not all zip code got the estimates. I checked 4 counties in California, about 70% got the numbers the for 5 year estimates of 2019. Not sure if it is due to the sampling, so some zip code area is just too small to get the estimates? Once 2020 zip code data released, then i will be able to get data for all zip code area? any suggestions you have to get zip code population data to me?

    Thanks in advance.


  • I just find an article, which partially answered my question. But what should I do?


    1. ZIP Codes are actually not areas with defined boundaries, and there are no official USPS ZIP Code maps. Areas must be derived using address files. The Census Bureau has done this in creating ZIP Code Tabulation Areas (ZCTAs).
    2. The Census Bureau publishes population data by ZCTA and boundary files for them. But ZCTAs are not strictly analogous with ZIP Codes; there isn’t a ZCTA for every ZIP Code, and if you try to associate ZIP data with them some of your records won’t match. You need to crosswalk your ZIP Code data to the ZCTA-level to prevent this.
    3. ZCTAs do not nest or fit within any other census geographies, and the postal city name associated with a ZIP Code does not correlate with actual legal or municipal areas. This can make selecting and downloading ZIP Code data for a given area difficult.
    4. ZIP Codes were designed for delivering mail, not for studying populations. They vary tremendously in size, shape, and population.
    5. Analyzing data at either the ZIP Code or ZCTA level over time is difficult to impossible.
    6. ZIP Code and ZCTA numbers must be saved as text in data files, and not as numbers. Otherwise codes that have leading zeros get truncated, and the code becomes incorrect.
  • Many people look down on zip codes but they can be useful when that's the only identifier you have for people (from an address) -- don't give up based on that -- 

  • A few years ago, we developed a ZIP Code to ZCTA Crosswalk for a project, which we've published, but since then, I found this site, which seems committed to maintaining a reasonably current crosswalk:


  • Any idea what source they use for ZIP Code boundaries? This is pretty important, since there is no authoritative map of ZIP Codes (there is no USPS map of ZIP Codes). Various third-party entities have used information from USPS to create their own ZIP Code maps. I've used Pitney-Bowes (formerly Maponics). I believe they update their maps monthly to reflect the latest changes in delivery routes, etc.

    Any crosswalk of ZIP Codes to ZCTAs should identify the source of the ZIP Code boundaries, with the date the boundaries reflect.

  • Thanks Joe, this is really helpful!

  • Thanks.

    The zip code information used in my project is from child care provider's address. We try to allocate the fund to subsidized  child care, based on the population information, like number of children, poverty, etc.