How to Write a Illinois Address (With Examples)

Address basics  |   |  2 min read

Here is how to write a mailing address in Illinois, with examples from Springfield and Chicago and the most common mistakes to avoid.

The standard format

RECIPIENT NAME STREET NUMBER AND NAME, UNIT CITY, IL ZIP CODE

The state is always written as IL, two capital letters with no periods. USPS prefers the city, state and ZIP on the same final line.

Example: Springfield

Sarah Thompson 7128 Ridge St Springfield, IL 62702

Example with an apartment in Chicago

Patricia Williams 453 Meadow Ave Apt 2B Chicago, IL 60633

Example with a PO Box

Luis Thompson PO Box 993 Springfield, IL 62712

PO Boxes often have their own ZIP code, separate from street addresses in the same town. Check the ZIP with the post office that holds the box.

Common mistakes

  • Writing the full state name or an old abbreviation instead of IL.
  • Putting the apartment number on a line below the street address.
  • Using a ZIP code from a neighboring city. One city can have many codes, but each street belongs to a specific one.

Counties and local details

Illinois is divided into 105 counties. The county does not appear in a mailing address, but it matters for sales tax, elections and some shipping rules, so many business systems store it separately.

Create realistic Illinois addresses for testing, with real cities, counties and ZIP codes.

Generate Illinois addresses