Centinela splits mail into 5 P.O. Boxes by housing area, with Facilities D and E sharing one box. Sending to the wrong box can delay a letter.
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Mail at Centinela State Prison is organized by housing area, but it’s simpler than some other CDCR institutions. CDCR’s official facility page for Centinela lists 5 P.O. Boxes: one for general institution mail, one each for Facility A, Facility B, and Facility C, and one shared box for Facilities D and E. There’s no separate box published for legal mail or inmate funds the way some other CDCR prisons list, so general institution mail covers those purposes too. Using the wrong facility box can still delay a letter, so this guide breaks down exactly which box to use.
CDCR’s own facility page for Centinela lists 5 P.O. Boxes, split by housing area:
| Purpose | P.O. Box |
|---|---|
| General institution mail (if you don’t know the facility) | P.O. Box 731, Imperial, CA 92251-0731 |
| Facility A | P.O. Box 901, Imperial, CA 92251-0901 |
| Facility B | P.O. Box 911, Imperial, CA 92251-0911 |
| Facility C | P.O. Box 921, Imperial, CA 92251-0921 |
| Facility D and Facility E (shared) | P.O. Box 931, Imperial, CA 92251-0931 |
This is a simpler setup than some other CDCR institutions, which publish separate boxes for legal mail and inmate funds on top of the housing-area split. Centinela’s page doesn’t list those as separate boxes, so use the general institution box or the correct facility box for all mail, including money orders, unless the institution tells you otherwise when you call.
If you know which facility the person is housed in, address personal letters and cards directly to that facility’s box:
[Full Legal Name, CDCR Number]
Centinela State Prison, Facility [A/B/C]
P.O. Box [901/911/921]
Imperial, CA 92251-[matching ZIP+4]
If the person is in Facility D or Facility E, both share the same box:
[Full Legal Name, CDCR Number]
Centinela State Prison, Facility [D/E]
P.O. Box 931
Imperial, CA 92251-0931
If you’re not sure which facility the person is in, use the general institution address instead:
[Full Legal Name, CDCR Number]
Centinela State Prison
P.O. Box 731
Imperial, CA 92251-0731
Unlike Facilities A, B, and C, which each have their own separate P.O. Box, Facilities D and E both route mail through the same box, P.O. Box 931. If the person you’re writing to is housed in either D or E, use this box; there’s no separate address to tell the two apart. Write the facility letter (D or E) on the envelope along with the person’s name and CDCR number so mailroom staff can route it correctly inside the institution.
Regardless of which box you’re using, always write the person’s full legal name and their CDCR number on the envelope. This is how CDCR staff route mail internally to the correct housing unit.
People do get transferred between CDCR institutions, and they can also move between facilities within Centinela itself. Check CIRIS at ciris.mt.cdcr.ca.gov, or ask the person directly, to confirm they’re still at Centinela, and which facility they’re currently in, before you send a letter, especially if some time has passed since you last heard from them.
Standard letters, greeting cards, and photos are generally accepted. Keep to plain paper and cards without stickers, glitter, tape, or anything glued on, since those items get mail rejected.
Photos are generally allowed within CDCR’s limits: no Polaroids, since the backing can conceal contraband, and nothing larger than 8x10. Avoid nude or sexually explicit images, gang-related content, and anything depicting drugs or weapons, which will be rejected. There’s usually a limit on how many photos per envelope, so send a reasonable number and confirm current limits with the institution if you plan to send many. You can also send photos through Pigeonly without printing anything yourself. Upload the photos online and Pigeonly prints and mails them to Centinela for you.
Centinela’s facility page doesn’t list a separate box for legal mail the way some other CDCR institutions do. If you’re an attorney or legal representative, mark your envelope clearly as legal mail and call (760) 337-7900 to confirm the current handling process and correct address for it, since legal mail is opened only in the presence of the incarcerated person to check for contraband, not read.
Incoming personal mail is opened and inspected for contraband before delivery. If a piece is rejected, the person is typically notified and told why, and the item may be returned to sender or held. Following the plain-paper, no-attachments rules is the best way to avoid a rejection.
You can’t mail a personal package straight to the person. Approved packages, including quarterly packages, come through CDCR’s contracted package vendor, which the person or an approved family member orders from. Contact the institution at (760) 337-7900 or check CDCR’s approved vendors page for the current process.
Don’t mail cash. Since Centinela’s facility page doesn’t list a separate inmate funds box, send a money order or check to the general institution box, P.O. Box 731, Imperial, CA 92251-0731, or the person’s specific facility box, and confirm the correct address by calling (760) 337-7900 before mailing a large amount. You can also send an electronic deposit through GTL/ConnectNetwork, JPay, or Access Corrections. See the CDCR send-money guide for the full process, fees, and how restitution affects deposits.
6 of 12 questions
It depends on the housing facility. If you don't know the facility, use the general institution box, P.O. Box 731, Imperial, CA 92251-0731. If you know the facility, use its specific box: Facility A is 901, Facility B is 911, Facility C is 921, and Facilities D and E share box 931.
MailCentinela splits mail by housing facility to help route it faster. It's a simpler system than some other CDCR institutions, since Centinela doesn't publish a separate legal-mail or inmate-funds box, only 5 total boxes.
MailIt can delay delivery while staff reroute it to the correct housing area. If you're not sure which facility the person is in, use the general institution box, P.O. Box 731, instead of guessing.
MailAsk the person directly, or check CIRIS at ciris.mt.cdcr.ca.gov. If you can't confirm which facility they're in, use the general address, P.O. Box 731, Imperial, CA 92251-0731, instead of guessing.
MailCDCR's facility page lists one combined box, P.O. Box 931, for both Facility D and Facility E at Centinela. Write the specific facility letter on the envelope along with the person's name and CDCR number so mailroom staff can route it correctly.
MailCheck CIRIS at ciris.mt.cdcr.ca.gov, or ask the person directly, especially if it's been a while since your last letter, since transfers between CDCR institutions and between facilities within Centinela do happen.
MailYes, within CDCR's limits: no Polaroids and nothing larger than 8x10. Avoid nudity, gang references, and images of drugs or weapons, which get rejected. There's usually a per-envelope limit, so send a reasonable number. You can also send photos through Pigeonly, which prints and mails them for you.
MailNew books and magazines generally must come directly from an approved publisher or vendor, not mailed by you personally. Check CDCR's approved vendors and disapproved-publications rules before ordering.
MailNo. Personal packages aren't accepted directly. Approved packages come through CDCR's contracted package vendor, ordered by the person or an approved family member.
MailCentinela's published facility page doesn't list a separate legal-mail box. Mark your envelope clearly as legal mail and call (760) 337-7900 to confirm the correct address and current handling process before mailing.
MailStickers, glitter, tape, glued-on items, cash, Polaroids, oversized photos, and any content seen as contraband, gang-related, or explicit. Stick to plain paper and cards.
MailNever send cash. Mail a money order or check to the general institution box, P.O. Box 731, Imperial, CA 92251-0731, or the person's facility box, confirming the correct address by phone first, or use an electronic deposit through GTL/ConnectNetwork, JPay, or Access Corrections. See the CDCR send-money guide for details.
MailConfirm the person is still housed here and which facility before you mail.
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All information on this page comes directly from official government and facility sources. How we verify information › Last verified July 20, 2026.