# Illinois license plate: Trailer semi

> The Illinois trailer semi license plate: format 9999 ST, for example 1204 ST, 1999 to today, trailer. What each character means, its sizes and sources.

Page: https://vehiclesdb.com/license-plates/united-states--illinois/trailer-semi · Markdown version of the HTML page, which is canonical. Site map: https://vehiclesdb.com/llms.txt · Terms of use: https://vehiclesdb.com/legal/terms

Part of [Illinois license plates](https://vehiclesdb.com/license-plates/united-states--illinois) (8 registration series).

![Illinois (United States) license plate, Trailer semi (1999 to today)](https://vehiclesdb.com/plates/us-il/us-il-trailer-semi/illinois-license-plate-trailer-semi.svg)

| Fact | Value |
|---|---|
| Format | `9999 ST` (9 any digit) |
| Years | 1999 → today |
| Class | trailer |
| Issued for | trailer |
| Checking a registration | The format above follows the issuing rules: a registration that fits it is one this series could have issued. |
| Series id | `us-il-trailer-semi` (https://vehiclesdb.com/license-plates/united-states--illinois/trailer-semi) |

Sources:

- [3-412(a): one plate for a trailer or semitrailer](https://codes.findlaw.com/il/chapter-625-vehicles/il-st-sect-625-5-3-412.html)
- [3-413: trailers display at the rear only](https://codes.findlaw.com/il/chapter-625-vehicles/il-st-sect-625-5-3-413.html)
- [en.wikipedia.org](https://en.wikipedia.org/wiki/Vehicle_registration_plates_of_Illinois)
- [the stacked-character rule the ST reading rests on](https://www.aamva.org/getmedia/646bcc8a-219b-47d8-b5cd-726240473163/License-Plate-Standard-Edition-3_September-2025-Update.pdf)

## How numbers are issued

observed 1 S/T to 1032416 S/T (secondary)

## Use it

- Plate image (SVG): https://vehiclesdb.com/plates/us-il/us-il-trailer-semi.svg
- Make it with your own text: https://vehiclesdb.com/license-plate-generator/illinois?series=us-il-trailer-semi
- API: `GET https://vehiclesdb.com/api/v1/plates/us-il` returns this series as the entry with `"id": "us-il-trailer-semi"` (https://vehiclesdb.com/api)

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Open data, CC BY 4.0: reuse it with a visible credit to VehiclesDB and a link (https://vehiclesdb.com/legal/attribution). Plate images show sample serials and are not open data (https://vehiclesdb.com/legal/image-license). Dataset commit db0ec0a: https://github.com/vehiclesdb/vehiclesdb