What is a ZIP Code?
ZIP is an acronym for Zone Improvement Plan, and refers to the USPS’ initiative in the 1960’s to improve the sorting and delivery of mail. Units with roughly the same number of deliverable addresses were created and termed ZIP Code. ZIP Codes are comprised of 5 numbers. An additional four, referred to as ZIP +4, are appended by the USPS to allow mail to not only reach the postal town associated with a ZIP Code but also be sorted the city block, office building, or individual high-volume receiver of mail level.
