For this release, a thorough review of shoreline ZIP Codes was carried out in order to reassign small areas likely containing mailing addresses currently outside of the shoreline to the correct carrier route and 5-digit ZIP Code polygons. As a result of the generalization process run on shoreline ZIP Codes, there were instances where areas that included streets and homes were incorrectly located outside of their respective carrier route and ZIP Code boundaries.
The review was completed for the continental US (including Great Lakes states), Hawaii, and US territories. A separate review of Alaska will take place for a future release.