1. Find their inmate number and facility
Every letter needs the person's inmate ID number (also called a DOC number, booking number or, in federal prison, a register number). Look them up with the state's official inmate locator, or the Federal Bureau of Prisons locator for federal prisons. County jails usually have their own search on the sheriff's website.
Tip: Our Find an Inmate pages link to the official locator for every state, plus the federal locator.
2. Get the facility's mailing address
Use the mailing address listed on the corrections department's website, not the street address from a map. Many prisons receive mail at a PO Box, and a growing number send all personal mail to a central processing address that scans it (more on that below).
3. Address the envelope the right way
Put the person's full committed name and inmate number on the first line, then the facility name and mailing address. A typical format looks like this:
- John A. Smith #123456
- Name of Correctional Institution
- PO Box 000
- City, State ZIP
Always include your full name and return address in the top left corner. Most facilities won't deliver mail without one, and it's where they'll write back.
4. Keep the letter simple
- Plain white paper and a plain white envelope.
- Blue or black ink. Dark, clear writing scans and copies well.
- No stickers, glitter, perfume, lipstick, tape, staples or paper clips.
- Nothing tucked inside unless the facility allows it (photos have their own rules).
- Put your name and address on the letter itself too, in case it's separated from the envelope.
5. Know that mail may be scanned
Many state prison systems and county jails no longer hand out paper mail. Letters go to a processing center, get scanned, and the person reads them on a tablet or kiosk. The original is often destroyed. Your letter still arrives; it just arrives as an image, which is why plain paper and dark ink matter.
6. Be patient
Every letter is inspected before it's delivered, so allow anywhere from a few days to two weeks. Replies take just as long, and people inside often have to buy paper and stamps from commissary. A slow reply rarely means they aren't interested.