What is a ZIP Code Database?

What is a ZIP Code Database?

Our ZIP Code Database is a listing of all U.S. ZIP Codes put into row and column format for easy use and manipulation. It contains over 100 unique fields of information and covers every ZIP code in the United States and Territories. It gives you a virtually unlimited number of ways to analyze all the U.S. Census Demographic and ZIP Code list information. ZIP Code lists are a great tool for marketing, building websites, demographic analysis, store locator, and general analysis.

The data comes in 4 different file types, all of which are made available to you. You can download the ZIP Code Database in Access, Excel, CSV, and SQL for quick and easy importing into anything you need. We also provide FTP Access in order for you to automated the delivery of the Database every month as well as an API for programmatic access.

How many types of ZIP Codes are there?

The U.S. Postal Service maintains 4 distinct types of ZIP Codes, known by their Classification Code:

• <BLANK>: General. Used for general mail delivery.
• P: P.O. Box. Used for mail deliveries to contract mail boxes only.
• U: Unique. Used for large volumes of mail. Ex: Bank of America, Berkeley, IRS.
• M: APO/FPO Military. Used for mail to service men and women stationed overseas.

The ZIP Code Database contains a 'Classification Code' column indicating each ZIP Codes type by its letter. This allows you to select only the exact ZIP Code types you need or check is a provided ZIP Code has special limitations (most companies cannot ship to Military ZIP Codes).

ZIP Code are not Geographic Divisions

Most people think of ZIP Codes as the last piece in geographic divisions: Nation > State > County > City > ZIP Code. This is not true. ZIP Codes were created exclusively for the expedient delivery of mail with mail routes designed to best suite the needs of the USPS. ZIP Codes do not always adhere to national nor local geographic boundaries and limits.

ZIP Codes are not required to observe City, County, nor State boundaries when those boundaries interfere with a mail carriers route. To put it in perspectve, imagine being a postal employee placing mail in mailboxes down a long street. It would be highly inconvenient to stop and turn around due to an imaginary line.

ZIP Codes are Not Cities

ZIP Codes have nothing to do with cities. While a ZIP Code has a city name, it is for reference to area it serves. A ZIP Code may also have names for other towns, villages, or well known neighborhoods. For example, ZIP Code 90291 is for Venice, CA. Venice is a residential, commercial, and recreational neighborhood with a statistically significant population of over 28,000 and located within the city limits of Los Angeles, CA. Even the ZIP Code boundary for 90291 do not match the neighborhood boundary for Venice, CA that is generally accepted. It is not possible to compare data for ZIP Code cities to data compiled at the city municipality level, because the boundaries that constrain each are very different.

The map to the left illustrates the disparity between boundaries. Los Angeles City Limits are shown in gray, the Venice Neighborhood Boundary in green outline, and the 90291 ZIP Code Boundary in red.

ZIP Codes that exist outside of city limits will likely have a city name of the larger area that it serves. Towns, Villages, and other well known places might be placed in the City Alias column for identification. Each record has a "MailingName" column that idicates if this name is acceptable for mailing purposes.

Do ZIP Codes Cross County Lines?

Yes. In fact, over 20% of all ZIP Codes cross county boundaries. Our ZIP Code Database indicates this with the 'Multi County' column. The Business version offers a separate table detailing all counties a ZIP Code covers. The 'primary' county is assigned to each record and is usually based on the part that receives the highest volume of mail. ZIP Codes cross state lines as well if needed, but this is much rarer. As with cities, you cannot compare data for ZIP Codes in a County to County data because the boundaries for each do not match.