A letter can be the highlight of someone's week inside. But facility mailrooms reject huge volumes of mail every day over small, avoidable mistakes. Here's how to write a letter to an inmate that actually gets delivered.
Start with the right address and inmate ID
This is where most letters fail. Every piece of mail must include the inmate's full committed name and their ID number, addressed exactly the way the facility specifies. A missing or wrong ID number is the number-one reason mail is returned. Confirm both using an inmate search before you send anything.
Know the facility's mail rules
Rules vary widely, but common restrictions include:
- Page limits (some facilities cap letters at a set number of pages)
- White paper and standard ink only — no markers, crayon, or colored paper at some sites
- No stickers, glitter, tape, perfume, lipstick, or stained paper
- Photo limits (size, quantity, and no Polaroids or explicit content)
- No staples, paper clips, or anything that could conceal contraband
How to find the address and inmate ID
You can't send mail without two things: the facility's mailing address and the inmate's identification number (sometimes called a booking number, DOC number, or register number). Start with an inmate search to confirm where your loved one is held, then use the facility's official roster or department of corrections locator to get the exact mailing format. Federal inmates have a register number through the Bureau of Prisons; state inmates have a DOC number; county detainees usually have a booking number. Mixing these up, or using an old number after a transfer, is a frequent cause of returned mail.
How to format and address the envelope
Most facilities want mail addressed in a specific order. A typical format looks like this:
- Line 1: Inmate's full committed name and ID number
- Line 2: Facility name
- Line 3: Facility street address or PO box
- Line 4: City, State, ZIP
Include your full return address in the top-left corner — mail without one is often rejected outright. Use a plain white envelope, write legibly in blue or black ink, and don't decorate the outside. Always double-check the current requirements for that specific facility, because the order and wording can differ from one institution to the next. For exact, real-world examples for county jail, state prison, and federal mail, see our guide on how to address mail to an inmate.
Write something worth receiving
You don't need to be a poet. The most meaningful letters simply share everyday life: what the kids are up to, how the garden's doing, a funny thing that happened at work. Avoid discussing the case, anything that could be read as coded, or details that might cause problems if read by staff — all mail is subject to inspection.
What not to write
- Anything about the pending case or legal strategy
- References to drugs, violence, gang activity, or contraband — even as a joke
- Other people's personal information
Can you send books, cards, or magazines?
Often yes, but with rules. Many facilities enforce a "publisher-only" policy, meaning books and magazines must be shipped new, directly from an approved retailer or publisher — not sent from your home. Greeting cards are usually fine if they're plain (no musical chips, glitter, or padding). Hardcover books are restricted at some institutions. When in doubt, check the facility's mail policy before ordering, or use a service that already knows the rules.
What about electronic messages?
A growing number of facilities support electronic messaging through providers like JPay, CorrLinks (the federal email system), or ViaPath's GettingOut app. These can be faster than physical mail, but they require the inmate to have an account, often charge per message or per "stamp," and aren't available everywhere. Not sure which company serves your loved one's facility? Our inmate service provider directory breaks down who runs what. Physical letters remain the most universal option — almost every facility accepts them, and many people treasure a handwritten note in a way a screen can't match.
Ideas for staying consistent
The hardest part of writing to someone inside isn't the first letter — it's the tenth. Set a simple rhythm: a short note every week, a photo once a month, a card on birthdays and holidays. Consistency matters more than length. Even a few lines that say "I'm thinking of you" can anchor someone's week and remind them they haven't been forgotten.
The easy way: let us print and mail it
If keeping track of each facility's rules feels overwhelming, our send letters service handles it for you. You type your letter or upload photos, and we format everything to the facility's requirements, print, add postage, and mail it — so you can focus on what to say, not the fine print.
Letters work best alongside other forms of connection
A handwritten note or photo is meaningful, but it's one piece of staying close. You can complement regular letters with a care package — facility-approved snacks, hygiene items, and essentials that provide physical comfort between your messages. Not sure what's actually allowed? See what you can send in a care package. Our discounted phone calls service lets you stay in voice contact for a flat $10 a month for 500 minutes instead of paying the facility's standard per-minute rate. And if your loved one is still in pretrial detention, our bail bonds service connects you with a licensed agent who may be able to secure their release so the letters stop being necessary.
What to do if your letter is returned
If a letter comes back, don't take it personally — it's almost always a rules issue, not a rejection of you. Check the most common culprits first: an incorrect or outdated inmate ID, a missing return address, prohibited contents, or the person being transferred or released. Confirm the inmate's current facility and number with a fresh inmate search, fix the issue, and resend. If you're unsure what triggered the return, the facility's mailroom can usually tell you their specific reason.
Making photos count
Photos are one of the most meaningful things you can send, and they follow their own rules. Facilities typically limit the number of photos per envelope, ban anything larger than a standard print, and prohibit Polaroids (the backing can conceal contraband) as well as explicit or gang-related images. Print on standard photo paper, write the inmate's name and ID lightly on the back if allowed, and avoid sending originals you can't replace. A handful of everyday snapshots — the kids, the dog, a holiday meal — can mean more inside than almost anything else.
Quick checklist before you send
- Correct committed name + inmate ID number
- Exact facility mailing address
- Within page and photo limits
- No prohibited materials (stickers, stains, etc.)
- Nothing about the case or anything that reads as coded