Data Files
Main Data Sources and Updates
USPS Database
Monthly update
Database 2010-2021
Please contact us for your specific needs.

County District Data

Available products in the current market and their problems

There are "County by Zip Code" and "County by Census Block, Block Group and/or Tract" county data files. Following are common problems that our competitors have:

in Current Market

"5 Digit Zip Code to County" District Data
. 5 digit zip codes cross county lines, sometimes straddling deep into two or more counties.
. PO Boxes may serve more than one county.
"9 Digit Zip Code to County" District Data
. Leaves out large regions in which mail is not delivered to residences. Holes in data make whole sections of counties disappear from the applications in which they are used.
"Census Block, Block Group and/or Tract to County" District Data
Census Block, Block Group, and Tracts are all designed by the U.S. Census TIGER/Line team to not cross county lines. These entities are the basic building blocks of the TIGER/Line files and are used for all statistical analyses done by the Census Bureau. Census blocks and the block groups and tracts built from them are created and re-aligned with the decennial census.

Census block files do not stay current with newly created addresses. The 2011 U.S. Census blocks will be the most accurate yet produced by the US Government. However, on the day it is published, it will already be a year or more behind the additions to addresses and changes in U.S. Postal zip code assignments. As good as they are for demographic analysis and Census reports of demographic trends, they contain no zip+4 or carrier route information and cannot be used reliably for directing mail campaigns or targeting mailings to the census block or tract level.

USgeocoder Solutions

100% accuracy for existing addresses, 98% accuracy for new addresses

Using its proprietary algorithms, USgeocoder combines census block data and U.S. Postal Addressing data to assign new addresses to census block, block group, tract, zip+4 and carrier route to the entire country and is possessions. USgeocoder can assign these addresses with a 98% accuracy.

Most frequently updated data you can find

USgeocoder is installed with 2019 Census TIGER data.

Every month, USgeocoder uses US Postal Service data to update the TIGER/Line census files. Typically, a new address is available to USgeocoder within thirty days after the Postal Services' first delivery to it.

Here is the sample header of "County by Zip Code" data files.

Zip 5

Zip 4


USgeocoder also offers "Address Range-To-County" for better accuracy. Here is the sample header of "Address Range-To-County" data fils.

Address Low

Address High


We can produce custom data files per your specifications. Files are available annually, semi-annually, quarterly, or monthly. They may be purchased by state, region, or the whole country. Please contact us for flexible options and pricing details.

You can use USgeocoder data files in many ways:

- Use our data files in your own GIS applications or demographic analysis software
- Let us batch process your address data for district matching
- Get REALTIME information for your address via USgeocoder API
- Display and explore your data with USgeocoder's GIS mapping engine

USgeocoder also provides demographic services and custom GIS application development.
Contact us to see how we can help.