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How to send a letter to an inmate at Pennington County Jail

To write to someone held at Pennington County Jail, address the envelope to the inmate's full name and booking number, Pennington County Jail, 307 St Joseph St, Rapid City, SD 57701. Pennington County Jail is the jail for Pennington County, South Dakota, run by the Pennington County Sheriff's Office. Mail is opened and inspected — include your full return address, and double-check the person is still in custody, since people are released or moved from a county jail quickly.

Inmate mail — Pennington County Jail

[Inmate's full name]  [booking number]
Pennington County Jail
307 St Joseph St
Rapid City, SD  57701

Put the inmate's full name and booking number on the first line, and your full return address in the corner — mail without either is usually rejected.

Verified September 2026penmateapp.com

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Mail a letter to an inmate — $5

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Your name
Your return address

Pennington County Jail307 St Joseph StRapid City, SD 57701

Your letter, printed and mailed for you.

Key facts

  • Send mail to Pennington County Jail, 307 St Joseph St, Rapid City, SD 57701 — the jail's own mailroom.
  • Write the inmate's full name and booking number on the envelope, plus your full return address, or the letter is returned.
  • All incoming mail is opened and inspected for contraband before it reaches the inmate.
  • Do not enclose cash, checks, gift cards, or anything other than paper — prohibited items get the whole letter rejected.
  • Non-legal mail is opened, inspected, and screened before delivery; legal mail is opened in the detainee's presence.
  • Mail without a return address is not delivered.
  • Only new books and magazines sent directly from the publisher are accepted.
  • County jails move fast — people are released, bailed out, or transferred within days. Confirm the person is still in custody before mailing anything time-sensitive.
  • PostPal prints and mails your letter for you the next business day for $5 — with your return address printed so they can write back, and no printer, envelope, or stamp needed.

How to send your letter

  1. 1

    Confirm the person is still at the jail

    County-jail populations turn over quickly. Check the Pennington County Sheriff's Office's online inmate roster to confirm they're still at Pennington County Jail — and get their booking number — before you mail anything.

  2. 2

    Address it correctly

    First line: the inmate's full name and booking number. Then Pennington County Jail, 307 St Joseph St, Rapid City, SD 57701. Add your full return address in the top-left corner.

  3. 3

    Keep the contents allowed

    A plain letter on white paper is always safest. Non-legal mail is opened, inspected, and screened before delivery; legal mail is opened in the detainee's presence. No cash, gift cards, or any object other than paper.

  4. 4

    Send it without a printer

    Write or upload your letter in PostPal with this address prefilled, and we print, envelope, and mail it via USPS the next business day for $5 — your return address printed so they can reply.

Common questions

How do I address a letter to an inmate at Pennington County Jail?

Put the inmate's full name and booking number on the first line, then Pennington County Jail, 307 St Joseph St, Rapid City, SD 57701. Include your full return address in the top-left corner of the envelope.

Is mail to Pennington County Jail opened or read?

Yes. All incoming mail is opened and inspected for contraband before delivery, and non-legal mail can be read.

What if they've been released or moved?

It happens fast at a county jail — people bond out or transfer within days, and the letter won't be forwarded. Check the Pennington County Sheriff's Office's inmate roster to confirm they're still at Pennington County Jail before you send.

What can I send to Pennington County Jail?

Non-legal mail is opened, inspected, and screened before delivery; legal mail is opened in the detainee's presence. Mail without a return address is not delivered. Only new books and magazines sent directly from the publisher are accepted. When in doubt, a plain letter on white paper is always accepted.

Can the inmate write back to me?

Yes, if you include a complete return address. PostPal prints your return address on the letter for you.

Sources

Addresses verified September 2026 against official sources. Always confirm on the official site before time-sensitive filings.

See the full US county & city jails rules — what you can and can’t send, photos & more →

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