Random Illinois Address Generator

Chicago’s grid: every address has a direction

Chicago numbers its streets from one zero point: State Street divides east from west and Madison Street north from south. Eight hundred numbers make a mile, so 2400 N is three miles north of Madison and 4000 W five miles west of State. Because a street such as Ashland Avenue runs both north and south of Madison, the direction is part of the address: 1650 N Ashland Ave and 1650 S Ashland Ave are about four miles apart. Drop the N or S and the address becomes ambiguous. Every generated Chicago address carries its direction; suburban ones only sometimes, as in real data.

Chicago, the suburbs and the collar counties

Cook County alone has well over a hundred municipalities. Evanston, Oak Park, Cicero and Schaumburg border Chicago but have their own governments and tax rates, and DuPage, Kane, Lake, McHenry and Will counties add more. Many suburban ZIP codes cover parts of two or three municipalities, and some postal city names differ from the municipality the house is in. Use the suburbs in the generator to check that your jurisdiction logic does not assume “ZIP code = city”.

ZIP codes 600 to 629

Illinois ZIP codes run from 60001 to 62999. Chicago itself is 606, the northern and western suburbs are 600–605, Rockford is 611, Peoria 616, Springfield 627 and the Metro East across the river from St. Louis — Belleville, East St. Louis — 620–622.

Area codes from 312 to 618

Downtown Chicago is 312 and the rest of the city 773, with 872 overlaying both. The inner western and southern suburbs are 708/464, the north and northwest suburbs 847/224, the west suburbs 630/331, Rockford and Joliet 815/779, central Illinois 217/447, Peoria 309/861 and southern Illinois 618/730.

Sales tax on a Illinois address

State rate: 6.25%. Illinois charges 6.25% state sales tax on general merchandise, and home-rule cities, counties and transit districts add their own. Chicago’s combined rate of 10.25% is among the highest of any large US city, while a suburb a few streets away can be two points lower. Illinois is a good place to test that a tax engine resolves rates by exact address rather than by ZIP code, because many suburban ZIP codes cross municipal lines.

Cities in the Illinois generator

The generator picks one of these 20 places, then one of its real ZIP codes and one of its area codes. Illinois has 1,575 ZIP codes in 1,286 places in the data we use.

Illinois ZIP code prefixes

The first three digits of a ZIP code identify the sectional center facility that sorts its mail. Illinois uses 29 prefixes; each is shown with the place that has most of its ZIP codes and how many codes it holds.

Illinois area codes

Phone numbers in generated addresses always use 555-0100 to 555-0199, the block the North American Numbering Plan reserves for fiction, so they never ring a real line.

Sources

• GeoNames US postal codes (CC BY 4.0): ZIP codes, places and counties
• North American Numbering Plan area code assignments
• Illinois Department of Revenue – sales tax rates
• City of Chicago – street numbering

Checked October 2026. Street names and house numbers in the generator are synthetic. General US address format, ZIP code structure and form-testing tips are on the US address generator page; ZIP codes on their own come from the ZIP code generator.

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