A US Zip Code is a 5-digit number where the first digit represents a certain group of U.S. states, the second and third digits together represent a region in that group (or perhaps a large city) and the fourth and fifth digits represent a group of delivery addresses within that region. For example, Zip Code is 11742 serves Holtsville City under Tehama County, New York State.

ZIP Code zones in the United States

States of the United States