About US Zip Codes

USA is a large country with 50 states and a federal district.  Each state has a number of counties, parishes or boroughs, depending on the state.  For example, Alaska has boroughs instead of counties, whereas Louisiana has parishes.  In 1963, United States Postal Services started a postal code system known as ZIP code to make process of mail delivery easier.  ZIP actually stands for Zone Improvement Plan.  The basic 5-digit format was first introduced in 1963 and later extended to add an additional 4 digits after a dash to form a ZIP+4 code. This additional 4 digits help USPS more effectively group mail for delivery.

US Zip Codes

States vs Counties vs Cities

Matching ZIP Codes with States, Counties, and Cities can be tricky.  They weren’t made to correspond to existing boundaries such as cities, counties, or even states.  Each city may have more than one ZIP code as the ZIP code “boundary” will cross the county or state lines.

If you need a ZIP code database, you can download latest ZIP codes for majority of cities and counties across the USA.  Total 43,777 records including city and county names, state abbreviations and individual ZIP code.  Just follow instructions below to download the file.

Our ZIP code database will be useful for bulk use, for example to match city to zip code.  We sourced the data from Census Bureau as well as popular US real estate sites.

Review of the ZIP Codes database
  • Format and compatibility
  • Database completeness
  • Availability


CSV file format is popular and easiest use. Compatible with major data processing tools such as MS Excel, SAS and ACL. 51 states and federal district. This ZIP database is available for everyone at no cost.