Illinois inmate mail
Send a letter to an inmate in Illinois
Confirm the current Illinois facility and IDOC number, then write online. PieterPost formats, prints, adds the envelope and postage, and mails your physical letter to the facility address you provide.
Choose their Illinois facilityIllinois state-prison addresses
Find the current Illinois facility mail address
Illinois personal mail goes to the individual's current correctional facility, where non-privileged letters, cards, and photographs are scanned or photocopied in color. Confirm the facility after every transfer.
Illinois does not use one statewide external P.O. box for personal letters. Use the facility's inmate-mail address, not a visiting, money, package, or street address.
Address format
Three simple steps
How to send a letter to an inmate in Illinois
Choose the current facility and add the inmate's IDOC number. We help you carry the address into the letter flow.
- 1Choose their current facility
- 2Write and review your message
- 3We print, stamp, and mail it
Current Illinois guidance
Helpful inmate-mail rules
- Letter length
- There is no fixed page cap; 10 or more one-sided pages, or five or more double-sided sheets, are delivered as photocopies
- Paper format
- Use paper no larger than 8.5 by 14 inches; black ink is strongly recommended for a clear scan
- Envelope and address
- Include the full committed name, IDOC number, sender name, and return address, and use the current facility's inmate-mail address
- How it arrives
- The facility provides a color digital or printed reproduction; the physical original is not normally delivered
Items that need another approved route
PieterPost is for ordinary written letters. To help avoid a mailroom rejection, do not add these items to the envelope:
- Glue, adhesives, stickers, or glued and layered objects
- Glitter, paint, crayon, ribbon, cloth, string, or other hard-to-scan decoration
- Thick, musical, pop-up, glittered, or adhesive-heavy cards
- Cash, checks, stamps, loose valuables, or irreplaceable originals
PieterPost takes care of the rest
You only need to write your message
No printer, paper, envelope, stamp, or trip to the post office. We prepare and mail the physical letter for you.
- Write your letter online from any device
- Check the finished letter before paying
- We format and print it for the facility
- We address, stamp, and mail the envelope
Illinois facility finder
Find their prison or local jail
Choose the current facility on the map. We will carry the selected address into the letter flow for you to review.
Is the person in federal prison?
Search the Bureau of Prisons inmate locator and continue with the federal letter flow.
Common questions
How do I send a letter to someone in Illinois state prison?
Use Illinois IDOC's custody search to confirm the current facility and IDOC number, then write online with that facility's inmate-mail address. PieterPost formats, prints, envelopes, adds postage, and mails the physical letter.
Which address should I use for Illinois inmate mail?
Illinois has no universal personal-mail P.O. box. Use the full committed name and IDOC number, current correctional facility, and that facility's published inmate-mail address.
How do I find the IDOC number and current facility?
Use the Illinois individual-in-custody search to confirm both the IDOC number and current institution. Recheck before mailing because a transfer changes the correct destination.
How does letter length affect delivery in Illinois?
Illinois does not publish a fixed cap on ordinary correspondence. Mail with 10 or more single-sided pages, or five or more double-sided sheets, is delivered as physical photocopies instead of being uploaded to a tablet. Smaller accepted mail may be delivered digitally or as a reproduction.
Does this guide apply to Illinois jails or federal prisons?
No. This page covers adults in Illinois Department of Corrections state prisons. County or city jails, federal prisons, juvenile facilities, and other custody systems may use different addresses and handling.