Counties by ZIP Code Database

ZIP Codes cross county lines about 20% of the time. Many ZIP Codes span several counties and some even cross state lines. This Counties by ZIP Code product was created to identify ZIP Codes that span multiple counties (ZIP Code to County database), isolate one-to-one County to ZIP Code relationships, and/or identify all ZIP Codes within a given county’s boundary.

zip code to countyThis is a one-to-many (ZIP Code to County) database. The file includes: all counties by ZIP Code, an estimate of the county percentage covered by each ZIP Code, a sequence showing the predominate counties for each ZIP Code, and much more (see features at right).

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Database Specs & Features

Download Sample Data (CSV)

  • Immediate Download

    Download is available immediately upon purchase and for the duration of the annual subscription.

  • Quarterly Updates

    A monthly update of this database is not necessary, so we update our database quarterly and recommend that you download quarterly as well.

  • Free FTP/SFTP (upon request)

    To update your database without human intervention, we can provide an FTP address for you to write a script to access. Just request it after purchase.

  • Data Format - CSV

    Comma-Separated Values (CSV) Text File

  • 5 Digit ZIP Code

    Official U.S. Postal Service five digit ZIP Code

  • County

    The name of the county in which the ZIP Code is found. This is a one-to-many (ZIP Code to County) relationship.

  • County FIPS

    Federal Information Processing Standard (FIPS) 3‐digit county. FIPS codes are not available for all areas (APO, FPO, some U.S. Territories).

  • Percentage

    This is the percentage of the zip code area which this county occupies. If there is only one county for the zip code it will be '100'. This is a rounded number, so there could be cases where not all totals equal 100%.

  • Sequence Number

    This is for prioritizing the counties within a ZIP Code (sequence 1 is the main county for the ZIP Code).

  • State

    Official U.S. Postal Service state abbreviation

  • State FIPS

    Federal Information Processing Standard (FIPS) 2‐digit state. FIPS codes are not available for all areas (APO, FPO, some U.S. Territories).

  • City

    Official city name used by the U.S. Postal Service