The ZIP codes in Illinois range from 60001 to 62999. Three-digit ZIP code prefixes are assigned to every state in the United States, and the prefixes assigned to Illinois span from 601 to 629.Continue Reading
The ZIP code system was introduced by the United States Postal Service to efficiently locate destinations for mail. The Sectional Center Facility is a processing and development center for the USPS. The three-digit prefixes assigned to Illinois by the SCF include Palatine (600, 602, 610-611), Carol Stream (601, 603), South Suburban (604), Fox Valley (605) and Chicago (606-608).
Some other three-digit prefixes in Illinois include Champaign (609, 617-619, 624), Quad Cities (612), Peoria (613-616) and Springfield (623, 625-627). The prefixes 620, 622, 628 and 629 are served by SCF in St. Louis, Missouri. The ZIP code prefix 621 is not in use in Illinois. The three-digit prefix denotes the sectional area or large city, whereas the two digits that follow them denote the post office facility or delivery area.
The ZIP+4 code was introduced by the USPS in 1983 to further narrow the delivery area to a more specific location. The syntax for a ZIP+4 code is -, where the added +4 code is denoted by a hyphen.Learn more about Public Records