Counties by ZIP Code Database

Multiple Counties Per ZIP Code

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.

This 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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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 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.

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  • 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)