Legal Mail vs. Personal Mail at Yellowstone County Detention: Where to Send Each and How to Label It

At Yellowstone County Detention,

Label Package

• ✓ Label or stamp the envelope clearly with “LEGAL MAIL”.
• ✓ Address it to the inmate’s name (not just the facility).
• ✓ Include a return address that shows the sending entity’s name (attorney, law firm, court, etc.) and a phone number for verification.

The return address details aren’t just formality - Yellowstone County Detention uses them to verify that the sender is actually an attorney, law firm, court, or other legitimate legal entity. Including the sending entity’s name and a working phone number helps staff confirm the source, which can prevent the piece from being questioned, delayed, or treated like regular correspondence.

Send legal mail directly to the facility’s street address: 3165 King Ave E Billings, MT 59101 This is the physical facility address for legal mail - not the third-party P.O. Box used for personal mail scanning.

1. Don’t route legal or medical mail through the personal-mail scanning process - send it directly to the facility at 3165 King Ave E, Billings, MT 59101.
2. Make sure it’s truly legal mail - it needs to come straight from the inmate’s attorney or a court, and it should be clearly labeled “LEGAL MAIL.”
3. Double-check the sender details before mailing - include the sending entity’s name and a phone number on the return address so the facility can verify the source.