Counties by ZIP Code Database

Multiple Counties Per ZIP Code

ZIP Codes span more than one county around 20% of the time. Many ZIP Codes cross several counties and some even cross into other states. This Counties by ZIP Code database identifies and lists ZIP Codes that span multiple counties along with an approximation of the ZIP Code's coverage area within the county. It can be used to isolate one-to-one County to ZIP Code relationships and to identify all ZIP Codes within a given county’s boundary.

It is a one-to-many (ZIP Code-to-County) database and 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, plus much more (see features at right).

Annual Subscription

30-Day Money-Back Guarantee


Highly Accurate

At GreatData, we earnestly pursue creating databases that are current, accurate, and precise. Quality over quantity is our commitment to you.

Annual Subscription

Keep your systems current by regularly downloading database updates during your subscription period.

Quarterly Updates

Based on frequency of change, we recommend you download the latest version of this particular database on a regular basis.

Download Options

Immediate download link from our site, a free utility for custom files, or an FTP directory (upon request) auto updated as new releases occur.

Multiple Counties per ZIP Code

This product is ideal for applications where its critical to have a ZIP Code to County database showing all counties by ZIP Code. For example:
  • Tax calculations
  • Insurance rate calculations
  • HMO coverage area determination
  • Sales territory assignments
  • Fraud detection
  • Data Verification
Learn more: View the Product Documentation / Watch our Multiple Counties by ZIP Code video / Watch our Accuracy Matters video

Database Specs

Data Format - CSV

Comma-Separated Values (CSV) Text File

5 Digit ZIP Code

Official U.S. Postal Service five digit ZIP Code


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).


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).


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).


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

Database Sources

We are licensees of USPS database products, but we enhance our ZIP Code to County database based on decades of experience to provide you with the most accurate product available.

Affordability and Simplicity

  • Low Cost
  • One Year Access
  • Updated Quarterly
  • Unlimited Downloads
  • Unlimited User Licensing Available
  • Money Back Guarantee


Cannot be resold, transferred, or used to compete with (as outlined in our license agreement).

Related Links

Counties by 9-digit ZIP Code (ZIP+4)