Auxiliary File Overview

Use auxiliary files to match against special data that is not included in the GeocodeUSAddress database.

The GeocodeUSAddress database is updated regularly to incorporate changes made by the USPS and third-party data vendors. You may have newer information that has not yet been incorporated. Auxiliary files provide a way for you to process your input records against a file that includes these changes.

Note: ReverseGeocodeUSAddress does not support auxiliary files.

There are two types of auxiliary file records:

Street Records—Contains a range of one or more addresses on a street. For required fields, see Auxiliary File Layout. A street record must not have secondary address information mailstops, Private mail boxes (PMBs), and PO Boxes.
Landmark Records—Represents a single site. For required fields, see Auxiliary File Layout. A landmark record must not have street type abbreviations, predirectional and postdirectional abbreviations, or low and high house numbers.

Note: You cannot update the auxiliary file while GeocodeUSAddress is running. If you want to update the auxiliary file, stop GeocodeUSAddress before attempting to replace or edit the file.